Methods and systems for processing a microelectronic topography

ABSTRACT

Methods and systems are provided which are adapted to process a microelectronic topography, particularly in association with an electroless deposition process. In general, the methods may include loading the topography into a chamber, closing the chamber to form an enclosed area, and supplying fluids to the enclosed area. In some embodiments, the fluids may fill the enclosed area. In addition or alternatively, a second enclosed area may be formed about the topography. As such, the provided system may be adapted to form different enclosed areas about a substrate holder. In some cases, the method may include agitating a solution to minimize the accumulation of bubbles upon a wafer during an electroless deposition process. As such, the system provided herein may include a means for agitating a solution in some embodiments. Such a means for agitation may be distinct from the inlet/s used to supply the solution to the chamber.

PRIOR APPLICATION

This application is a continuation application from prior applicationSer. No. 10/462,167 filed Jun. 16, 2003 now U.S. Pat. No. 6,881,437.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to methods and a system for processinga microelectronic topography, particularly for processes associated withan electroless deposition process.

2. Description of the Related Art

The following descriptions and examples are not admitted to be prior artby virtue of their inclusion within this section.

Electroless plating is a process for depositing materials on a catalyticsurface from an electrolyte solution without an external source ofcurrent. An advantage of an electroless deposition process is that itcan be selective, i.e., the material can be deposited only onto areasthat demonstrate appropriate chemical properties. In particular, localdeposition can be performed onto metals that exhibit an affinity to thematerial being deposited or onto areas pretreated or pre-activated,e.g., with a catalyst. The material or catalyst applied onto theselected areas is sometimes called a “seed material” or “seed layer” andthe ratio of the deposition rate on the activated regions to thedeposition rate at the non-activated regions is known as the “depositionprocess selectivity.” For many applications, it is important to providea deposition of high selectivity. Other important characteristics of anelectroless deposition process are uniform thickness and adherence ofthe deposited layer to the substrate.

Most conventional electroless deposition processes include a series ofsolution baths. Such a series of baths are used for preparing a surfacefor the electroless deposition process, as well as the processesincluding and subsequent to the deposition process. Such a processconfiguration, however, facilitates the deposition of foreign particlesand/or contaminants on a substrate surface when transferring thesubstrates from bath to bath. Another common problem with treating asurface in a series of baths is the exposure of the substrate surface toair during the transfer between baths. Such an exposure to air may causeoxidation of the substrate surface that will result in poor catalyticactivity and poor quality metal deposits. This problem becomesespecially troublesome when using materials that easily oxidize in air,such as copper. In an attempt to overcome these problems, some equipmentmanufacturers have proposed apparatuses which process a substrate in onechamber for a plurality of different process steps associated with anelectroless deposition process.

Such apparatuses, however, fail to prevent the solutions from theplurality of different process steps from mixing once they are expelledfrom the process chamber. Consequently, the apparatuses may not reuseprocess solutions within the apparatus, incurring higher material costsand waste disposal costs for the electroless deposition process. Inaddition, such apparatuses fail to provide a manner with which to supplyair exterior to the process chamber during processing, such as for adrying step, for example. In particular, prior art apparatuses may onlyoffer two modes of operation, one in which the chamber is sealed forprocessing and another in which the chamber is not sealed for loading.In other cases, prior art apparatuses may not be sealed at all. In anyembodiment, another problem with conventional process chambers is themanner in which a substrate is secured within the process chamber. Inparticular, few conventional process chambers offer a manner with whichto secure a substrate without causing damage to the substrate,particularly along the edges of the substrate.

One common drawback of existing electroless deposition processes andapparatuses is low speed of deposition. For example, a typicalelectroless deposition process does not generally exceed 100 nm/min. Thedeposition rate of an electroless process may generally depend on thematerial to be deposited and, therefore, the deposition rate may be muchlower than 100 nm/min, in some cases. For example, the speed ofdeposition of a cobalt-tungsten-phosphorus layer may be within betweenapproximately 0.01 nm/min and approximately 10 nm/min. In general, thedeposition rate of an electroless process may depend on characteristicsof the activated areas, such as dimensions, profiles of the exposedsurfaces, and distances between the portions of the areas to beactivated. In some embodiments, the deposition rate of an electrolessprocess may further depend on the temperature of the solution used todeposit the material. In particular, the deposition rate may increasewith increases in temperature. However, many electroless depositionsolutions tend to decompose at high temperatures, leading to significantnon-uniformities in the deposited material. On the other hand,deposition rates of electroless solutions at relatively low temperaturesmay be undesirably low, reducing production throughput and increasingfabrication costs.

Another common problem with electroless deposition processes is theformation of gas bubbles on the substrate surface during processing. Ingeneral, the formation of gas bubbles may be due to the evolution ofhydrogen during the reduction-oxidation process of the electrolessdeposition process and/or by a high level of hydrophobicity within thesubstrate of the wafer. The gas bubbles undesirably prevent a materialfrom being deposited uniformly upon a substrate surface, potentiallydepositing a layer outside the specifications of the process.

In some embodiments, electroless deposition may be used for theformation of metal features within integrated circuits. In fact,electroless deposition techniques may be particularly advantageous forforming copper features within a microelectronic topography, which wellmatches the present trend for using copper as interconnect materialsinstead of aluminum, tungsten, silicides, or the like. In addition,electroless deposition techniques are favorable for depositing materialsinto deep holes within the topography that cannot be uniformly coveredby other deposition techniques, such as sputtering and evaporation, forexample. As such, an electroless deposition process may be advantageousfor depositing a metal material using a dual damascene process.

In some microelectronic devices, a trench comprising a metal feature mayalso include a liner layer and a cap layer to prevent the diffusion ofthe bulk metal layer within the metal feature to underlying andoverlying layers of the topography, respectively. In some cases,however, it may be difficult to clean and activate the barrier layer fora sufficient deposition of a bulk metal layer. In particular, thebarrier layer may be cleaned and activated for the deposition of thebulk metal layer, but it may be difficult to prevent the surface frombeing contaminated between processes. In addition or alternatively, itmay be difficult to selectively deposit or align a cap layer upon thebulk metal layer such that no other metal adheres to the dielectricportions of the topography arranged adjacent to the metal feature. Inembodiments in which a bulk metal layer is polished to be confinedwithin the sidewalls of a trench, the dielectric portion of thetopography arranged adjacent to the metal feature may include smallfragments of the bulk metal layer upon its upper surface. The smallfragments may be catalytic to the electroless deposition of the caplayer or may attract a catalytic seed layer used to electrolesslydeposit the cap layer. In either case, portions of the cap layer may beundesirably deposited upon the dielectric portion, potentially causing ashort within the circuit.

As such, it would be advantageous to develop a system and methods forprocessing a microelectronic topography, particularly for processesassociated with an electroless deposition process. For example, it wouldbe desirable to develop a system which is configured to conduct one ormore process steps within a chamber without taking a microelectronictopography arranged therein out between steps. In addition, it would bebeneficial to have a system which prevents process solutions from mixingupon being dispensed from the process chamber. Such a process chambermay be further adapted to secure a wafer within the chamber as well ashave a means to provide an air passage to the chamber during processing.In some cases, the process chamber may be additionally or alternativelyadapted to prevent the generation and accumulation of bubbles upon awafer surface during processing. In addition, the process chamber may beconfigured to offer a manner with which to increase the boiling point ofan electroless deposition solution used within the chamber. Additionalbenefits may also be realized by methods which offer to provide abarrier layer which is not contaminated by particles prior to anelectroless deposition process and which is either autocatalytic or isreadily available for the deposition of a catalytic seed layer. Inaddition, it may be advantageous to develop a method which prevents thedeposition of a cap layer upon dielectric portions of a topography.

SUMMARY OF THE INVENTION

The problems outlined above may be in large part addressed by improvedsystems and methods for processing a microelectronic topography. In someembodiments, the systems and method may be specifically used forprocesses prior to, during, and subsequent to an electroless depositionprocess. However, the system and methods described herein are notnecessarily restricted to such processes. In general, a system isprovided which is adapted to conduct one or more processes within aprocess chamber. In some embodiments, the system may be adapted toconduct a succession of processes without having the microelectronictopography removed from the process chamber. Alternatively, however, thesystem may be used to conduct a single process. In either case, thesystem described herein may include a process chamber having a pluralityof auxiliary equipment arranged therein and coupled thereto. Forexample, the system may include a plurality of supply lines, storagetanks, process control devices, and temperature and pressure gauges. Inaddition, the process chamber may include a substrate holder, aplurality of inlets and outlets, a loading port, and a plurality ofother components, such as a gate, for example. It is noted that theplurality of components and methods provided herein are not co-dependentand, therefore, may not necessarily be employed together. In particular,the system described herein may be constructed to include anycombination of the components described below. In addition, the methodsfor processing a microelectronic topography, as described herein, mayinclude any one or a plurality of the methods discussed below.

In general, the system described herein may be adapted to form a firstenclosed area about and including a substrate holder of a processchamber of the system. In some embodiments, however, the system may beadapted to form another, smaller enclosed area about and including thesubstrate holder. Such an adaptation to form two different enclosedregions may entail the process chamber to include at least two outerportions configured to couple with each other and form the firstenclosed region and at least two inner portions configured to couplewith each other and form the second enclosed region. As noted above, insome embodiments, the system may be adapted to perform a succession ofdifferent process steps within the process chamber. In such anembodiment, the system may be further adapted to couple the outerportions prior to the succession of the different process steps. In somecases, however, the system may be adapted to uncouple the outer portionsfor a drying process of the microelectronic topography. Alternatively,the outer portions may not be uncoupled for such a drying process.

In either case, the system may be adapted to couple and uncouple theinner portions between the different process steps without uncouplingthe outer portions. For example, in some cases, the system may beadapted to couple the inner portions prior to an electroless depositionprocess and uncouple the inner portions subsequent to the electrolessdeposition process. Consequently, the system may be adapted to dispensedifferent processing fluids into the first and second enclosed areasduring the different process steps. “Fluids,” as used herein, may referto liquids, gases, or plasmas, including gases in a standard state or anexcited state (i.e., a photon-activated gas state). The fluids in any ofsuch states of matter may be used at pressures below, at, or aboveatmospheric pressure as well as at temperatures associated with therespective process step of the fabrication process. In some embodiments,the process chamber may include a first outlet within one of the outerportions and a second outlet within one of the inner portions. In somecases, the process chamber may be adapted to prevent processing fluidsin the first enclosed area from entering the second outlet. For example,the process chamber may include a means for spinning the microelectronictopography. In particular, the process chamber may be adapted to spinthe microelectronic topography at a particular rate, such as betweenapproximately 0 rpm and approximately 8000 rpm, or more specificallybetween approximately 40 rpm and approximately 1200 rpm when the innerportions are uncoupled. In contrast, the microelectronic topography mayor may not be spun when the inner portions are coupled.

A method for processing a microelectronic topography using a chamberadapted to form different enclosed regions about a substrate holder iscontemplated herein. In particular, the method may include loading themicroelectronic topography into a process chamber and closing theprocess chamber to form a first enclosed area about the microelectronictopography. The formation of the first enclosed area may, in someembodiments, include moving a cover plate toward a base plate of theprocess chamber. In yet other embodiments, however, the formation of thefirst enclosed area may include moving the base plate toward the coverplate or moving the cover plate and base plate toward each other. Ineither case, the method may further include supplying a first set offluids to the first enclosed area to process the microelectronictopography in one or more process steps. Subsequently, the method mayinclude forming a second, distinct enclosed area about themicroelectronic topography and supplying a second set of fluids to thesecond enclosed area to further process the microelectronic topographyin one or more other process steps.

In some cases, the first set of fluids may include fluids for preparingthe microelectronic topography for an electroless deposition process,while the second set of fluids may include a deposition solution for theelectroless deposition process. In such an embodiment, the method mayfurther include reforming the first enclosed area subsequent to the stepof supplying the second set of fluids and supplying a third set offluids to the reformed first enclosed area to further process themicroelectronic topography. Alternatively, the first set of fluids mayinclude a deposition solution for an electroless deposition process, andthe second set of fluids may include fluids for processing themicroelectronic topography subsequent to the electroless depositionprocess.

In any case, the method may further include spinning the microelectronictopography. Such a spinning step may be conducted while the first and/orsecond set of fluids is supplied to the process chamber. In someembodiments, spinning the microelectronic topography may be furtherconducted during the formation of the first and/or second enclosedareas. In general, the rate at which to spin the topography may dependon the material supplied to the process chamber. In particular, arelatively high spin rate may be needed for fluids with a relativelyhigh viscosity, while a relatively lower spin rate may be needed forfluids with a relatively low viscosity. As such, the spin rate of thetopography when the first and second sets of fluids are supplied to theprocess chamber may be similar or may be substantially different. In anycase, the microelectronic topography may generally be spun at a ratebetween approximately 0 rpm and approximately 8000 rpm, or morespecifically between approximately 40 rpm and approximately 1200 rpm,depending on the viscosity of the fluid supplied to the process chamber.In some embodiments, the topography may be rotated at a sufficient rateto prevent fluids from entering a certain outlet as stated above.

As noted above, the process chamber may have a gate attached thereto insome embodiments. As such, a process chamber is provided which includesa wall with an opening and a gate casing arranged adjacent to the wallsuch that an opening within the gate casing opening is spaced laterallyadjacent to the wall opening. In some cases, the gate casing may bearranged such that the gate casing opening is spaced in direct lateralalignment with the wall opening. In such an embodiment, the wall openingand the gate casing opening may include dimensions large enough to allowone or more wafers to be loaded within the process chamber. In yet otherembodiments, the openings may not necessarily need to have dimensionsthat large, particularly when the gate is simply used to provide an airpassage to the process chamber as described below. As such, the gatecasing may not necessarily be arranged such that the gate casing openingis in direct lateral alignment with the wall opening.

In either case, the process chamber may further include a gate latchconfigured to align barriers of the gate latch with the wall opening andthe gate casing opening. In some embodiments, the gate latch isconfigured to move within the space between the wall and gate casing. Inthis manner, the gate latch may be configured to move the barriers suchthat the barriers are not in alignment with the wall opening and gatecasing opening as well. In some cases, the portion of the gate latchcomprising the barriers may be configured to move such that the twoopenings are either sealed or provide an air passage to the processchamber when the barriers are respectively aligned with the twoopenings. In this manner, the barriers may prevent fluids within theprocess chamber from flowing through the wall opening and gate casingopening whenever the barriers are respectively aligned with the twoopenings. In some embodiments, the process chamber may be adapted todraw air through the air passage and into the process chamber.

Consequently, a method for processing a microelectronic topographywithin a process chamber having such a gate is provided herein. Themethod may include loading a microelectronic topography into a processchamber. Such a step of loading may include introducing themicroelectronic topography through an opening of the process chamberthat serves as a loading port of the chamber, which may or may not havethe gate arranged adjacent thereto. The method may further includesealing the loading port or another opening within the process chamberwith a gate. In some cases, the step of sealing may include moving thegate such that barriers of the gate are in alignment with the opening ofthe process chamber. Alternatively, the gate may be fixed adjacent tothe opening. In either case, the method may further include exposing themicroelectronic topography to a first set of process steps. In someembodiments, the first set of process steps may include electrolesslydepositing a layer upon the microelectronic topography as well asprocess steps conducted prior to or subsequent to an electrolessdeposition process. However, the method is not restricted to suchprocess steps.

The method may continue on with opening the gate such that an airpassage is provided to the process chamber. The microelectronictopography may then be exposed to a second set of process steps withoutallowing liquids within the process chamber to flow through the airpassage. In some embodiments, the second set of process steps mayinclude drying the microelectronic topography. In addition oralternatively, the second set of process steps may include any otherprocess steps with which to process a microelectronic topography. In anycase, the method may further include removing the microelectronictopography from the process chamber subsequent to exposing thetopography to the first and second set of process steps. In cases inwhich the gate is arranged adjacent to a loading port of the processchamber, the step of removing may include moving the gate such thatbarriers of the gate do not block the opening of the process chamber.

As noted above, the process chamber may include a substrate holder withwhich to support a wafer for processing. In some embodiments, thesubstrate holder may be configured to prevent a substantial amount ofmovement of the wafer during processing. In particular, the substrateholder may, in some embodiments, include a clamping jaw adapted toprevent substantial movement of a wafer arranged upon the substrateholder. Such a clamping jaw may include a lever arranged along an edgeof the substrate holder and a support member pivotally coupled to thelever. In some cases, the clamping jaw may be one of a plurality ofclamping jaws spaced within the substrate holder. In general, the levermay include a first portion and a second portion. In some cases, thefirst portion may be longer than the second portion. In addition oralternatively, the first portion may be heavier than the second portion.In any case, the second portion may include a lip extending into a waferreceiving area of the substrate holder. In general, the clamping jaw maybe configured to lower the lip upon the wafer or to a level spaced abovethe wafer.

Since the elemental composition of a process fluid may directly affectthe reaction rate and uniformity of treating a microelectronictopography, process fluids may need to be analyzed and adjusted prior tobeing supplied to process chamber 22. As such, the system describedherein may include analytical test equipment for monitoring fluids usedwithin a process chamber. In general, the analytical test equipment maybe used to measure the concentration of elements within the processfluid. In this manner, it can be determined whether the process fluid isin specification or if the process fluid needs to be adjusted. Suchanalytical test equipment may be coupled to any supply line of thesystem, including those coupled to inlet and outlets of the processchamber. In addition or alternatively, the analytical test equipment maybe coupled to directly to the process chamber or to one or more storagetanks configured to hold process fluids used within the process chamber.

In some embodiments, it may be particularly advantageous to be able toanalyze four or more components within a system. For example,embodiments in which the system is used for a plurality of processes,such as the processes conducted prior to, during, and/or subsequent toan electroless deposition process, the adaptation of being able tomeasure the concentration of at least four elements may be advantageoussince the fluids used for the different process steps may have differentcompositions. In yet other embodiments, it may be advantageous to employanalytical test equipment with such an adaptation for processes whichuse solutions with a plurality of elements. An exemplary process using asolution with at least four elements is described in more detail belowin which a four-element barrier layer is deposited. In such anembodiment, it may be particularly advantageous for the analytical testequipment to be configured to measure the concentration of at least fourelements selected from the group consisting of boron, chromium, cobalt,molybdenum, nickel, phosphorus, rhenium, and tungsten. In any case, thesystem may further include a central processing unit (CPU) coupled tothe analytical test equipment. Such a CPU may include a carrier mediumcomprising program instructions executable on a computer system foradjusting compositions of the fluids based upon the analysis performedby the analytical test equipment.

In general, the system described herein may be adapted to provide anyprocess fluid for processing a microelectronic topography to a processchamber, including liquids, gases, and/or plasmas. In some embodiments,it may be particularly advantageous to perform a process using a singlephase. For example, employing a single liquid phase environment mayoffer a manner with which to control the pressure within the processchamber. In general, increasing the pressure of a solution mayadvantageously increase the boiling point of the solution. Inembodiments of electroless deposition, an increase in the boiling pointof the deposition solution may increase the temperature at which thesolution decomposes and may further allow the rate of deposition to beincreased. As such, a method for electrolessly depositing a layer upon amicroelectronic topography exclusively using a liquid phase iscontemplated herein. In general, the method may include loading thewafer into an electroless deposition chamber, sealing the electrolessdeposition chamber to form an enclosed area about the microelectronictopography, and filling the enclosed area with a deposition solution. Insome cases, filling the chamber may include pressurizing the enclosedarea to a pressure between approximately 5 psi and approximately 100psi, increasing the boiling point of the deposition solution. In someembodiments, the method heating the deposition solution to a temperatureless than approximately 25% below the boiling point of the depositionsolution to increase a reaction rate of the deposition solution with themicroelectronic topography.

In some cases, a process chamber may include a particular configurationto process a microelectronic topography using a single-phase solution.For example, a process chamber is contemplated herein which includes asubstrate holder and a reservoir arranged above the substrate holder andwithin sidewalls of the process chamber. A method for using such aprocess chamber is also provided herein. In general, the process chambermay be adapted to move the reservoir proximate to the substrate holderand dispense the fluids contained within the reservoir into an enclosedarea laterally bound by the microelectronic topography and thereservoir. In some cases, the reservoir may include one or more valvesand the process chamber may be adapted to open the valves upon movingthe reservoir proximate to the substrate holder. Such valves may begenerally adapted to allow bi-directional flow of the fluids between thereservoir and the microelectronic topography. In some cases, thereservoir may additionally or alternatively include a hatch. In such anembodiment, the process chamber may be adapted to move the hatch withinthe reservoir upon moving the reservoir proximate to the substrate. Insome cases, the process chamber may be further adapted to rotate thehatch when the hatch is moved within the reservoir. In such anembodiment, it may be particularly advantageous to rotate the hatch atrate sufficient to prevent the accumulation of bubbles upon themicroelectronic topography during processing. In any case, the method ofprocessing the topography may terminate upon closing the hatch andraising the reservoir to a level spaced above the substrate holder.

Regardless of the configuration of the process chamber, a method forprocessing a microelectronic topography within a process chamber mayinclude replenishing the fluids provided to the chamber for processing.Such a step of replenishing may, in some embodiments, include wideningone or more outlet passages of the process chamber such that a compositesecond dispensing flow rate of the deposition solution through theoutlets is substantially equal to the first inlet flow rate of thedeposition solution. Alternatively, the step of replenishing may includedecreasing the first inlet flow rate of the deposition solution to asecond inlet flow rate that is substantially equal to the firstdispensing flow rate of the deposition solution through outlets of theprocess chamber. In yet other embodiments, the step of replenishing mayinclude decreasing the first inlet flow rate of the deposition solutionto the process chamber to a second inlet flow rate and widening one ormore of the outlet passages to a composite second dispensing flow rate,wherein the composite second dispensing flow rate is substantially equalto the second inlet flow rate.

In some cases, pressurizing the chamber may be advantageous forminimizing the generation and accumulation of bubbles upon a surface ofa wafer during an electroless deposition process. In addition oralternatively, positioning a wafer face-up within a processing chambermay reduce generation and accumulation of bubbles upon a wafer. In yetother embodiments, agitating a solution used for an electrolessdeposition process may further or alternatively minimize the generationand accumulation of bubbles upon a wafer surface. As such, a method mayminimizing the accumulation of bubbles upon a wafer during anelectroless deposition process is provided herein. In general, themethod may include loading the wafer into an electroless depositionchamber, sealing the electroless deposition chamber to form an enclosedarea about the wafer, and supplying a deposition solution to theenclosed area. In addition, the method may include agitating thedeposition solution to create an amount of motion sufficient to form alayer having substantially uniform thickness. In some cases, the methodmay further include pressurizing the enclosed area to a predeterminedvalue, such as between approximately 5 psi and approximately 100 psi. Inthis manner, the steps of agitating and pressurizing may collectivelyreduce the amount of bubbles formed upon the wafer during theelectroless deposition process. In addition or alternatively, the stepof loading the wafer may include positioning the wafer face-up withinthe electroless deposition chamber such that the generation of bubblesmay be further reduced.

In any case, agitating the deposition solution may be conducted inseveral different manners. For example, in some embodiments, agitatingthe solution may include spraying the deposition solution into theprocess chamber at a rate between approximately 0.1 gallons per minuteand approximately 10 gallons per minute. In addition or alternatively,the supply of the deposition solution may be pulsed into the processchamber at a frequency between approximately 0.1 Hz and about 10 KHz,for example. In yet other embodiments, the process chamber may include ameans for agitating a solution which is distinct from inlets and supplylines used to supply the deposition solution to the process chamber. Forexample, the process chamber may include a transducer configured tosupply acoustic waves, such as ultrasonic or megasonic waves, to thedeposition solution. In such an embodiment, the step of agitating mayinclude propagating the acoustic waves parallel or perpendicular to atreating surface of the wafer. In yet other embodiments, the step ofagitating may include propagating the acoustic waves at an angle betweenapproximately 0° and approximately 90° relative to a treating surface ofthe wafer.

In addition or alternatively, the process chamber may include a deviceconfigured to move through the deposition solution and above the waferduring processing. In some embodiments, the device may be configured tocome into contact with the wafer. In other embodiments, however, thedevice may be configured to not come into contact with the wafer. Ingeneral, the device may include any mechanism which may cause asufficient amount of agitation with which to remove and/or prevent theaccumulation of bubbles on the surface of the underlying wafer. Forexample, in some embodiments, the device may include a brush with aplurality of bristles to stir the fluid within the process chamber. Inyet other embodiments, the device may include a rod, block, propeller,or plate. Consequently, it is noted that the device may include anydesign and may traverse at any speed sufficient to cause a disturbancewith which to minimize the number of bubbles of a wafer surface. In anycase, the device may, in some embodiments, be adapted to dispense fluidsto the wafer surface.

In addition to providing methods for processing a microelectronictopography which correlate to the system described herein, methods forforming a contact structure or a via within a dielectric layer are alsoprovided. It is noted that the methods described below may be conductedusing the system described herein, but are not restricted to the use ofsuch a system. Furthermore, the different process steps used to form acontact structure are not necessarily co-dependent and, therefore, maybe performed independent of each other.

In some embodiments, the method for forming a contact structure or viawithin a dielectric layer may include forming a liner layer upon amicroelectronic topography and converting at least a portion of theliner layer to a hydrated oxide layer. In some cases, the step ofconverting may include exposing the liner layer to an oxidizing plasma.In yet other embodiments, the step of converting may include exposingthe liner layer to an oxidizing fluid. In either case, the liner layermay include a metal layer in some embodiments. For example, the linerlayer may include a metal selected from a group consisting of tantalum,tantalum nitride, tantalum silicon nitride, tantalum carbon nitride,titanium, titanium nitride, titanium silicon nitride, tungsten andtungsten nitride. In some embodiments, the liner layer may include acombination of such materials, such as a stack of tantalum nitride andtantalum or a stack of titanium and titanium nitride, for example. Ineither case, the step of converting a portion of the liner layer mayinclude forming a metal oxide layer. For example, in embodiments inwhich the liner layer includes tantalum and the hydrated metal oxidelayer may include tantalic acid. In yet other embodiments, the linerlayer may include a dielectric material, such as silicon nitride,silicon carbide, silicon carbon nitride, silicon oxycarbide, siliconoxycarbon nitride, and/or any organic materials generally known for usein microelectronic fabrication. In such an embodiment, a portion of theliner layer may be converted into a hydrated and oxidized dielectriclayer.

In any case, the method may further include depositing a metal layerupon the hydrated oxide layer. Consequently a microelectronic topographymay be formed which includes a hydrated oxide layer and a metal layerformed upon and in contact with the hydrated oxide layer. Morespecifically, in embodiments in which the liner layer includes a metal,a microelectronic topography may be formed which includes a hydratedmetal oxide layer and a metal layer formed upon and in contact with thehydrated metal oxide layer. In some embodiments, the metal layer may beelectroless deposited upon the hydrated oxide layer. In otherembodiments, however, the metal layer may be deposited using processesother than electroless techniques. In some embodiments, the method mayinclude converting the hydrated oxide layer to an oxide layer subsequentto the deposition of the metal layer. Such a conversion the hydratedoxide layer to the oxide layer may include heating the microelectronictopography to a temperature greater than approximately 400° C. In yetother embodiments, the method may include converting the hydrated oxidelayer a different material subsequent to the step of deposition themetal layer. For example, in an embodiment in which the hydrated oxidelayer includes a metal, the method may include converting a hydratedmetal oxide layer into a metal layer. Such a conversion of the hydratedmetal oxide layer to the different material may include annealing themicroelectronic topography in an ambient comprising hydrogen.

In yet other embodiments, the method for forming a contact structure orvia within a dielectric layer may additionally or alternatively includeselectively depositing a second dielectric layer upon a first dielectriclayer and selectively depositing a metal layer upon portions of thetopography arranged adjacent to the first dielectric layer such that thedeposition of the metal layer upon the first dielectric is minimized. Insome embodiments, the step of selectively depositing the seconddielectric layer may include depositing a hydrophobic material. Such ahydrophobic material may be deposited by exposing the microelectronictopography to dichlorodimethylsilane or any xylene material configuredto form a hydrophobic material. More specifically, the hydrophobicmaterial may be deposited using organic vapor deposition.

In some embodiments, the method may further include removing the seconddielectric layer subsequent to the step of selectively depositing themetal layer. In yet other cases, the second dielectric layer may remainwithin the microelectronic topography for further processing. In eithercase, a microelectronic topography may be formed which includes a metalfeature having a second metal layer formed upon and in contact with afirst metal layer. In addition, the microelectronic topography mayinclude a dielectric portion having a lower layer of hydrophilicmaterial and upper layer of hydrophobic material. In some embodiments,the dielectric portion may have a lower surface substantially coplanarwith a lower surface of the metal feature. In addition or alternatively,the upper surfaces of the lower layer and the second metal layer may besubstantially coplanar. In any case, the thickness of the upper portionmay be less than approximately 500 angstroms.

Another microelectronic topography which may be formed using the methodsdescribed herein may include a metal feature having a single layercomprises at least four elements lining a lower surface and sidewalls ofthe metal feature. In some embodiments, the single barrier layer mayinclude at least four elements selected from a group consisting ofboron, chromium, cobalt, molybdenum, nickel, phosphorus, rhenium, andtungsten. In addition, the concentration of elements within the singlebarrier layer may include three elements each comprising betweenapproximately 0.1% and approximately 20% of a molar concentration of thebarrier layer and a fourth element comprising the balance of the molarconcentration. In some embodiments, the fourth element may includecobalt or nickel. In some embodiments, the single barrier layer may beconfigured to substantially prevent oxidation. In addition oralternatively, the single barrier layer may be configured tosubstantially prevent diffusion of a bulk metal layer formed upon thesingle barrier layer to other layers within the microelectronictopography. In some embodiments, the metal feature may further include asecond single barrier layer comprising at least four elements arrangedupon and in contact with the bulk metal layer.

There may be several advantages to using the system and methodsdescribed herein. For example, a system is provided which is adapted toconduct one or more process steps within a chamber without removing thewafer arranged within the chamber. In this manner, the deposition offoreign particles and oxidation of the topography may be minimized. Inaddition, a process chamber is provided which prevents process solutionsfrom mixing upon being dispensed from the process chamber. Consequently,one or more of the process fluids used in the process chamber may berecycled, reducing material and waste disposal costs associated with theprocess. Moreover, a substrate holder is provided which is adapted tosecure a wafer within a chamber such that a wafer is not damaged duringprocessing. In addition, a gate adapted to provide an air passage to theprocess chamber during processing is provided. In this manner, ambientair exterior to the process chamber may be supplied to the processchamber for a drying process, for example. Furthermore, a method and asystem for reducing the generation and accumulation of bubbles upon awafer surface during processing is provided. As a result, asubstantially uniform layer may be deposited. In some cases, the methodand system described herein may increase the boiling point of anelectroless deposition solution used within a process chamber. Such anincrease in the boiling point may, in some embodiments, may be used toincrease the deposition rate of the layer, increasing productionthroughput of the system.

Additional benefits may also be realized by the method of hydrating thebarrier layer prior to an electroless deposition process. In particular,such a process may advantageously allow the barrier layer to be readilyavailable for the deposition of a catalytic seed layer while preventingthe accumulation of particulate matter upon the barrier layer.Consequently, a more uniform bulk metal layer may be deposited thereon.In embodiments in which the barrier is formed to include at least fourelements, the barrier layer may be autocatalytic and, therefore, may notneed the extraneous process steps of activating the barrier layer.Furthermore, the method which deposits a hydrophobic layer upondielectric portion of the topography prior to the deposition of a caplayer may advantageously prevent the deposition of a the layer upondielectric portions of a topography, potentially preventing theformation of a short within the device.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to theaccompanying drawings in which:

FIG. 1 depicts a schematic diagram of a system for processing amicroelectronic topography;

FIG. 2 a depicts a partial cross-sectional view of a gate attached to aprocess chamber in an open position;

FIG. 2 b depicts a partial cross-sectional view of the gate from FIG. 2a in an unsealed closed position;

FIG. 2 c depicts a partial cross-sectional view of the gate from FIG. 2a in sealed position;

FIG. 3 depicts a flow chart for processing a microelectronic topographyusing a process chamber with a gate attached thereto;

FIG. 4 depicts a partial cross-sectional view of a substrate holder;

FIG. 5 depicts a flow chart for processing a microelectronic topographyexclusively employing a liquid phase environment;

FIG. 6 a depicts a partial cross-sectional view of a process chamberwith a reservoir arranged above a substrate holder;

FIG. 6 b depicts a partial cross-sectional view of the process chamberof FIG. 6 a subsequent to lowering the reservoir toward the substrateholder;

FIG. 6 c depicts a partial cross-sectional view of the process chamberin which a hatch of the reservoir has been raised subsequent to thelowering of the reservoir in FIG. 6 b;

FIG. 6 d depicts a partial cross-sectional view of the process chamberin which the hatch of the reservoir has been lowered back down to thebase of the reservoir subsequent to the raising of the hatch in FIG. 6c;

FIG. 7 depicts a flow chart for minimizing the generation of bubblesupon a wafer surface during processing;

FIG. 8 a depicts a top view of a process chamber included within thesystem depicted in FIG. 1 having a plurality of inlets spatiallyarranged about a substrate holder;

FIG. 8 b depicts a top view of the plurality of spatially arrangedinlets of FIG. 8 a configured to project fluid in a different direction;

FIG. 9 a depicts a partial cross-sectional view of a process chamber inan open position;

FIG. 9 b depicts a partial cross-sectional view of the process chamberof FIG. 9 a in which outer portions are coupled to form a first enclosedregion;

FIG. 9 c depicts a partial cross-sectional view of the process chamberof FIG. 9 a in which inner portions are coupled to form a secondenclosed region;

FIG. 10 depicts a flow chart for processing a microelectronic topographyusing the process chamber of FIGS. 9 a-9 c;

FIG. 11 depicts a partial cross-sectional view of a microelectronictopography having a trench formed within a dielectric layer;

FIG. 12 depicts a partial cross-sectional view of the microelectronictopography of FIG. 11 subsequent to the formation of a liner layer uponthe upper surface of the topography;

FIG. 13 depicts a partial cross-sectional view of the microelectronictopography of in which an upper portion of the liner layer is hydratedsubsequent to the formation of the liner layer;

FIG. 14 depicts a partial cross-sectional view of the microelectronictopography in which a bulk metal layer is formed upon the hydratedsurface of the liner layer subsequent to the formation of the hydratedsurface in FIG. 13;

FIG. 15 depicts a partial cross-sectional view of the microelectronictopography in which the bulk metal layer is planarized subsequent to theformation of the bulk metal layer in FIG. 14;

FIG. 16 depicts a partial cross-sectional view of the microelectronictopography in which a hydrophobic dielectric layer is formed upon thedielectric layer subsequent to the planarization of the bulk metal layerin FIG. 15;

FIG. 17 depicts a partial cross-sectional view of the microelectronictopography in which a cap layer is formed upon the bulk metal layersubsequent to the formation of the hydrophobic dielectric layer in FIG.16; and

FIG. 18 depicts a partial cross-sectional view of the microelectronictopography in which the hydrophobic layer is removed subsequent to theformation of the cap layer in FIG. 17.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, exemplary embodiments of systems andmethods for processing a microelectronic topography are illustrated inFIGS. 1-18. More specifically, FIG. 1 illustrates an exemplaryembodiment of a system that may be used for processing a microelectronictopography, while FIGS. 2 a-10 show detailed illustrations of particularcomponents of the system in FIG. 1 as well as methods of using such asystem. Furthermore. FIGS. 11-18 illustrate a method for processing amicroelectronic topography which may be conducted using the system shownin FIG. 1 or any other system adapted for such a method. It is notedthat the plurality of component designs and methods illustrated in FIGS.1-18 are not co-dependent and, therefore, may not necessarily beemployed together. In particular, the system described herein may beconstructed to include any combination of the components described inreference to FIGS. 1, 2 a-2 c, 4, 6 a-6 d, 8 a, 8 b, and 9 a-9 c. Inaddition, the methods for processing a microelectronic topography, asdescribed herein, may include any one or a plurality of the methodsdiscussed in reference to FIGS. 3, 5, 7, and 10-18.

The system illustrated in FIG. 1 is designated, as a whole, by referencenumeral 20. In general, system 20 may include process chamber 22 withwhich to process a microelectronic topography. More specifically,process chamber 22 may be used for one or more processes steps used tofabricate a microelectronic device, such as depositing, etching,activating, polishing, cleaning, rinsing, drying, or any combination ofsuch processes. In a preferred embodiment, process chamber 22 may beused for any of the processes associated with an electroless depositionprocess, including any processes performed prior to, during, orsubsequent to an electroless deposition process. For example, in somecases, process chamber 22 may be used to activate a surface of amicroelectronic topography such that a layer may be subsequentlydeposited using an electroless process within process chamber 22 orwithin a different process chamber. In addition or alternatively,process chamber 22 may be used for polishing and/or cleaning anelectrolessly deposited layer as well as depositing a cap layer upon theelectroless deposited layer. In yet other embodiments, process chamber22 may be used for processes not associated with an electrolessdeposition process.

As shown in FIG. 1, process chamber 22 may have a plurality of auxiliarycomponents arranged therein and coupled thereto. In particular, processchamber 22 may include chamber walls, a cover, a substrate holder, ameans for dispensing fluids within the chamber, as well as a pluralityof other components as described in more detail below. In addition,process chamber 22 may be coupled to a plurality of supply lines,storage tanks, and process control devices, such as but not limited totemperature and pressure gauges. In general, the components of processchamber 22 may be made of or may have a surface coated with a chemicallystable material that can withstand the action of aggressive solutionsused within process chamber 22. Such a material may further be stablewith temperatures ranging between approximately −20° C. andapproximately 800° C. and pressures ranging between approximately 1 psiand approximately 150 psi. Examples of such materials are Teflon,ceramics of certain types, or the like.

In addition, process chamber 22 may be configured to be hermeticallysealed such that, in a closed state, the interior of process chamber 22may be isolated from an ambient exterior to process chamber 22. In thismanner, the pressure within process chamber 22 may be regulated. Morespecifically, process chamber 22 may be pressurized to a level greaterthan, equal to, or less than the pressure of the ambient exterior toprocess chamber 22. In some cases, the lower edge of the cover 24 may bebeveled to prevent accumulation of solution on the cover. As a result,cross contamination of fluids between processes may be prevented. Inaddition, process chamber 22 may be mounted at any angle relative to theposition illustrated in FIG. 1. In particular, process chamber 22 may bemounted with cover 24 above base 25 as shown in FIG. 1, with cover 24and base 25 side by side, or with base 25 above cover 24.

In general, process chamber 22 may be adapted to provide an opening withwhich to load one or more wafers upon substrate holder 48. Inparticular, process chamber 22 may include loading port 26 along chamberwall 23 as shown in FIG. 1. In general, one or more wafers may be loadedthrough loading port 26 via a mechanical arm installed outside processchamber 22. In some embodiments, process chamber 22 may include gate 28arranged adjacent to loading port 26 to control access to the interiorof process chamber 22. An exemplary configuration of gate 28 isillustrated in FIGS. 2 a-2 c and is described in more detail below. Asnoted in reference to FIGS. 2 a-2 c, however, gate 28 may not be used toallow a wafer to be loaded therethrough, in some embodiments. Rather,gate 28 may simply be adapted to provide an air passage to processchamber 22. As such, in some embodiments, gate 28 may not be arrangedadjacent to loading port 26. In yet other embodiments, process chamber22 may not include gate 28 at all. As such, in some cases, processchamber 22 may include an alternative means for providing access to theinterior of process chamber 22 such that a wafer may be positioned uponsubstrate holder 48. For instance, in some cases, loading port 26 may bepositioned along another portion of chamber wall 23. In yet otherembodiments, cover 24 may be configured to allow a wafer to be loadedonto substrate holder 48.

Turning to FIGS. 2 a-2 c, an exemplary illustration of gate 28 is shown.As shown in FIGS. 2 a-2 c, gate 28 may be coupled to chamber wall 23. Asnoted above, however, gate 28 may alternatively be arranged adjacent tocover 24. In general, gate 28 may provide access and/or an air passageto process chamber 22 as well as a manner with which to seal the processchamber. In particular, FIG. 2 a illustrates gate 28 in a position toprovide access to process chamber 22 such that one or more wafers may beloaded therein. FIG. 2 b, on the other hand, illustrates gate 28 in aposition to provide an air passage to process chamber 22 whileprohibiting fluid within the process chamber from escaping through gate28. The position of gate 28 to seal process chamber 22 is illustrated inFIG. 2 c.

In general, gate 28 may include gate latch 30 and gate casing 32. Asshown in FIGS. 2 a-2 c, gate latch 30 may be interposed between chamberwall 23 and gate casing 32. Gate casing 32 may have opening 34 and maybe arranged such that opening 34 is spaced laterally adjacent to opening26 within chamber wall 23. In some embodiments, gate casing 32 may bearranged such that openings 34 and 26 are in direct lateral alignmentwith each other as shown in FIGS. 2 a-2 c. In such an embodiment,openings 34 and 26 may include dimensions large enough to allow one ormore wafers to be loaded within the process chamber. In yet otherembodiments, openings 34 and 26 may not necessarily need to havedimensions that large. In particular, openings 34 and 26 may notnecessarily need to have dimensions large enough to allow one or morewafers to be loaded within the process chamber when gate 28 is simplyused to provide an air passage to process chamber 22 as described inmore detail below. In such an embodiment, openings 34 and 26 may notnecessarily be in direct lateral alignment with each other.

In general, gate latch 30 may be configured to align barriers 36 and 38with the openings 34 and 26, respectively. Such a configuration mayinclude sliding gate latch 30 between chamber wall 23 and gate casing32. Although FIGS. 2 a and 2 b indicate that such a sliding movement isstarted with gate latch 30 positioned below openings 34 and 26, gatelatch 30 may alternatively be positioned above the openings prior tosuch a movement. In yet other embodiments, gate latch 30 may havebarriers 36 and 38 permanently located in lateral alignment withopenings 34 and 26. In such an embodiment, gate latch 30 may not be usedto load a wafer into process chamber 22. Rather, gate latch 30 maysimply be used to provide an air passage to process chamber 22 and/orseal process chamber 22. In any case, when barriers 36 and 38 arerespectively aligned with openings 34 and 26, the portion of gate latch30 comprising barriers 36 and 38 may be configured to provide an airpassage to process chamber 22 as shown by dotted line 40 in FIG. 2 b ormay be configured to move such that the two openings are sealed as shownin FIG. 2 c. As noted above, the position illustrated in FIG. 2 b mayprovide an air passage to process chamber 22 while prohibiting fluidwithin the process chamber from escaping through gate latch 30. In thismanner, gate latch 30 may offer a manner with which to provide air toprocess chamber 22 while processing a wafer therein. Processes employingsuch an air passage may include, for example, a drying process. In someembodiments, process chamber 22 may employ a vacuum with which to drawair from the air passage.

In any case, a method for processing a microelectronic topography withina process chamber having a gate similar to gate 28 is depicted in FIG.3. In particular, FIG. 3 illustrates a method which includes loading amicroelectronic topography into a process chamber as shown in step 42.Such a step of loading may include introducing the microelectronictopography through an opening of the process chamber that serves as aloading port of the chamber. The method may further include sealing anopening of the process chamber with a gate as shown in step 43. In somecases, the gate may be used to seal the loading port of the chamber. Assuch, in some embodiments, the step of sealing may include moving thegate such that barriers of the gate are in alignment with the opening ofthe process chamber. In other embodiments, however, the gate may be usedto seal an opening of the chamber which is distinct from the loadingport of the chamber. In either case, the method may further include step44 in which the microelectronic topography is exposed to a first set ofprocess steps. In some embodiments, the first set of process steps mayinclude electrolessly depositing a layer upon the microelectronictopography as well as process steps conducted prior to or subsequent toan electroless deposition process. However, the method is not restrictedto such process steps.

As noted in FIG. 3, the method may continue onto step 45 in which thegate is opened such that an air passage is provided to the processchamber. The microelectronic topography may then be exposed to a secondset of process steps without allowing liquids within the process chamberto flow through the air passage as indicated in step 46. In someembodiments, the second set of process steps may include drying themicroelectronic topography. In addition or alternatively, the second setof process steps may include any other process steps with which toprocess a microelectronic topography. In any case, the method mayfurther include removing the microelectronic topography from the processchamber subsequent to exposing the topography to the first and secondset of process steps as indicated in step 47. In cases in which theloading port of the process chamber is surrounded by the gate casingcomprising the gate, the step of removing may include moving the gatesuch that barriers of the gate do not block the opening of the processchamber.

Returning to FIG. 1, process chamber 22 may include substrate holder 48with which to support a wafer. In particular, substrate holder 48 mayinclude platen 50 supported by shaft 52, which passes through base 25 ofprocess chamber 22. Although substrate holder 48 is shown to hold asingle wafer, other substrate holders configured to hold multiple wafersmay be alternatively arranged included within process chamber 22. Assuch, process chamber 22 is not restricted to processing a single wafer.Rather, process chamber 22 may be either adapted for batch processing(i.e., processing multiple wafers at once) or may be adapted to processwafers sequentially (i.e., processing one wafer at a time). In any case,substrate holder 48 may be arranged such that a wafer may be positionedhorizontally as shown in FIG. 1. In other embodiments, substrate holder48 may be arranged such that a wafer is positioned vertically. In yetother cases, substrate holder 48 may be arranged to have waferspositioned at an angle between 0° and 90° relative to base 25.

In either case, substrate holder 48 may be configured to rotate. Inparticular, the outer end of shaft 52 may be rigidly coupled to gearwheel 53, which may be driven into rotation by motor 54. Morespecifically, the output shaft of motor 54 may be coupled to gear wheel55 and gear wheels 53 and 55 may be interconnected via a synchronizationbelt 56 such that shaft 52 and, thus, substrate holder 48 may berotated. Such an adaptation to rotate may advantageously allow processfluids introduced into process chamber 22 to be uniformly distributedacross an entire wafer. As a result, the treatment performed upon thewafer may be more uniform. It is noted that the arrangement of thecomponents with which to rotate substrate holder 48 in FIG. 1 is merelyan exemplary configuration. As such, other configurations for rotatingsubstrate holders known in the microelectronic fabrication industry maybe used within system 20. In yet other embodiments, substrate holder 48may not be configured to rotate. Rather, process chamber 22 may includeother means with which to rotate a wafer. Alternatively, process chamber22 may not be configured to rotate a wafer at all.

In some cases, substrate holder 48 may be configured to secure a wafersuch that movement of the wafer relative to the substrate holder isminimized. An exemplary substrate holder having such a configuration isshown in FIG. 4. In particular. FIG. 4 illustrates a cross-sectionalview of substrate holder 48 securing wafer W above platen 50 by means ofclamping jaw 58. It is noted that illustration of the substrate holderin FIG. 4 is merely an exemplary configuration of a substrate holderthat may be included within the process chamber described herein. In noway is process chamber 22 is restricted to the inclusion of such aconfiguration. Consequently, process chamber 22 may additionally oralternatively include several other substrate holder configurations withwhich to support a wafer. For example, substrate holder 48 may, in someembodiments, include a vacuum-activated mechanism with which to secure awafer to the substrate holder.

As shown in FIG. 4, clamping jaw 58 may be arranged along the edge ofsubstrate holder 48 such that the edge of wafer W is secured. It isnoted that clamping jaw 58 may be one of a plurality of clamping jawsarranged along the periphery of substrate holder 48, but only oneclamping jaw is shown in FIG. 4 to simplify the drawing. As such, insome embodiments, the substrate holder illustrated in FIG. 4 may alsoinclude a clamping jaw along the opposite edge of substrate holder,although substrate holder 48 is not restricted to such a configuration.In general, the number of clamping jaws to include within a substrateholder may depend on the size of the wafer to be processed and/or thetype of processing to be conducted within the process chamber. Forexample, in some cases, the number of clamping jaws may be optimizedsuch that a wafer may be secured without having superfluous number ofjaws with which to complicate the substrate holder configuration. Ingeneral, the plurality of clamping jaws may have a substantially similarconfiguration as clamping jaw 58. In addition, the plurality clampingjaws may be uniformly or non-uniformly arranged about the periphery ofsubstrate holder 48.

In some embodiments, clamping jaw 58 may be configured to secure wafer Wwhen platen 50 includes moveable platen 60 arranged above fixed baseplaten 61. In other embodiments, however, the adaptations of platens 60and 61 may be reversed. In particular, platen 50 may include a fixedplaten arranged above a moveable platen. Although the configuration ofclamping jaw 58 to secure wafer W upon substrate holder 48 is describedbelow in reference to platen 60 being moveable and platen 61 beingfixed, clamping jaw 58 is not restricted to such a configuration. Inparticular, clamping jaw 58 may be modified to accommodate thealternative adaptations of platens 60 and 61. In this manner, theconcept of using a clamping jaw having the configuration describedherein may be used in either case.

In some embodiments, substrate holder 48 may be configured to receivewafer W directly upon moveable platen 60. In yet other embodiments,however, substrate holder 48 may be configured to support wafer W abovemoveable platen 60. For example, in some embodiments, substrate holder48 may include annular seal 62 arranged upon moveable platen 60 andconfigured to receive wafer W, as shown FIG. 4. Such an annular seal maybe used to seal the backside of wafer W to moveable platen 60 such thatprocess solutions used during treatment of the front side of the waferdo not contaminate the backside of the wafer. In any case, the areaabove moveable platen 60 and extending in from clamping jaw 58 to theother end of substrate holder 48 may be referred to as a “waferreceiving region”, as used herein. As shown in FIG. 4, shaft 52 mayinclude a central hole through which rod 63 may be inserted andconfigured to slide through. The upper end of rod 63 may be coupled tothe bottom of the movable platen 61 such that when an upward force isapplied to rod 63, moveable platen 60 may rise relative to fixed baseplaten 61 as shown in FIG. 4. In some embodiments, substrate holder 48may include pins 64 rigidly supported in fixed base platen 61 andslidingly inserted within openings of moveable platen 60. Such pins maybe configured to further support wafer W when moveable platen 60 islowered toward fixed base platen 61. In yet other cases, substrateholder 48 may not include pins.

In any case, clamping jaw 58 may be configured to move upon raisingmoveable platen 60 such that wafer W may be secured. More specifically,clamping jaw 58 may include lever 65 pivotally coupled to support member66, which may be rigidly attached to fixed base platen 61. In apreferred embodiment, lever 65 may include portion 67, which ispivotally coupled to support member 66, and portion 68 extending outwardfrom support member 66. In this manner, lever 65 may be tilted uponraising moveable platen 60. In some cases, portion 67 may be lighterand/or shorter than portion 68 to augment such a tilting motion. In yetother embodiments, however, there may not be a weight or lengthdistinction between portions 67 and 68. As shown in FIG. 4, portion 67may include lip 69 extending inward from support member 66. Upon tiltinglever 65, lip 69 may extend beyond the periphery of wafer W such thatvertical motion of the wafer is minimized or prohibited. In some cases,lip 69 may extend to a level spaced above wafer W. Such an adaptationmay be particularly advantageous for minimizing the amount of damagesustained to the edge of wafer W as shown in FIG. 4. In yet otherembodiments, however, lip 69 may come into contact with wafer W. Ineither case, support member 66 may be positioned such that the lateralmovement of wafer W is minimized. In this manner, the vertical andlateral movement of wafer W may be minimized through the use of clampingjaw 58.

Returning back to FIG. 1, system 20 may include one or more supply lineswith which to supply various fluids to process chamber 22. In addition,system 20 may include one or more reservoirs with which to store suchfluids. As noted above, process chamber 22 may be used for anymicroelectronic fabrication process, including but not limited to,depositing, etching, activating, polishing, cleaning, rinsing, drying,or any combination of such processes. As such, the various fluidssupplied to process chamber 22 may include any fluids, including liquidsand/or gases, used for the fabrication of a microelectronic device. Insome cases, however, the various fluids may be associated with processesthat treat a microelectronic topography prior to, during, and/orsubsequent to an electroless deposition process. For example, reservoir70 may include an electroless deposition solution, while auxiliary tanks72 a, 72 b, and 72 c may include fluids for the treatment of a waferprior to or subsequent to an electroless deposition process. Morespecifically, auxiliary tanks 72 a, 72 b, and 72 c may include variousfluids used for the activation, cleaning, rinsing, and/or drying of amicroelectronic topography prior to or subsequent to an electrolessdeposition process. In yet other embodiments, however, reservoir 70 andauxiliary tanks 72 a, 72 b, and 72 c may be used to store fluids formicroelectronic fabrication processes other than those associated withan electroless deposition process.

It is noted that system 20 is not restricted to the aforementioneddesignation of chemicals for reservoir 70 and auxiliary tanks 72 a, 72b, and 72 c. In particular, reservoir 70 may include may include any ofthe various fluids used for the activation, cleaning, rinsing, and/ordrying of a microelectronic topography prior to or subsequent to anelectroless deposition. In addition, any of auxiliary tanks 72 a, 72 b,and 72 c may include a deposition solution. Furthermore, system 20 maybe adapted to provide additional deposition solutions to process chamber22 in some embodiments. In particular, system 20 may include a pluralityof reservoirs and supply lines for supplying deposition solutions toprocess chamber 22, including solutions for electroless deposition andnon-electroless deposition. In this manner, process chamber 22 may beused for depositing different materials upon a wafer without having totake the wafer out of the chamber.

As shown in FIG. 1, reservoir 70 and auxiliary tanks 72 a, 72 b, and 72c may be coupled to inlet ports of process chamber 22 via supply lines.In particular, reservoir 70 may be coupled to supply line 74 andauxiliary tanks 72 a, 72 b, and 72 c may be coupled to supply lines 76a, 76 b, and 76 c. In some cases, reservoir 70 may be further coupled tosupply line 75, which is connected to the bottom of the process chamber22. Such an additional supply line may offer an alternative method oradditional means with which to introduce the fluid from reservoir 70.For example, supply line 75, in some embodiments, may be coupled to aninlet adapted to indirectly project a fluid on a wafer residing onsubstrate holder 48. Such an adaptation is described in more detailbelow with reference to the means for distributing fluids into processchamber 22.

In some cases, system 20 may include supply lines other than the onescoupled to reservoir 70 and auxiliary tanks 72 a, 72 b, and 72 c. Forexample, system 20 may include supply line 78 for supplying a rinsingsolution, such as deionized water, to process chamber 22. In addition oralternatively, system 20 may include one or more supply lines, such assupply line 80, for supplying a compressed gas to process chamber 22. Insome embodiments, the compressed gas may be inert and may be used tosimply further pressurize process chamber 22 as discussed in more detailbelow. In yet other embodiments, supply line 80 may be used to supply achemical reagent gas with which to process the wafer. In some cases, aplasma may be generated within process chamber 22 using the reagent gas.In such an embodiment, process chamber 22 may include an ionizing coilwith which to form the plasma. In yet other embodiments, a wafer may betreated with reagent gas in its gas phase.

Consequently, the reference of “fluids” to process a microelectronictopography, as used herein, may refer to liquids, gases, or plasmas,including gases in a standard state or an excited state (i.e., aphoton-activated gas state). The fluids in any of such states of mattermay be used at pressures below, at, or above atmospheric pressure aswell as at temperatures associated with the respective process step ofthe fabrication process. In any case, the fluid introduced throughsupply line 80 may, in some embodiments, be used to dry a wafer arrangedwithin process chamber 22. In yet other embodiments, supply line 80 maynot be used to dry a wafer. In any case, supply lines which are coupledto a moving part of process chamber 22, such as cover 24, for example,the supply lines may be made in the form of hoses or other flexiblepipings.

Although supply lines 78 and 80 are shown coupled to cover 24 in FIG. 1,supply lines 78 and 80, as well as supply lines 74, 75, 76 a, 76 b, and76 c may be coupled at any location along process chamber 22. Inaddition or alternatively, supply lines 78 and 80 may be coupled toother inlets of process chamber 22. For example, supply line 78 may beadditionally or alternatively coupled to dispensing arm 94 as shown inFIG. 1. Furthermore, although supply lines 78 and 80 are specificallyreferenced as respectively supplying a rinsing solution and compressedgas to process chamber 22, the lines are not restricted to such afunction. Rather, supply lines 78 and 80 may be used to supply any typeof fluid to process chamber 22. In yet other embodiments, supply lines78 and/or 80 may be omitted from process chamber 22. Similarly, any ofsupply lines 74, 75, 76 a, 76 b, and 76 c may be used to supply any typeof fluid to process chamber 22 or may, alternatively, be omitted fromprocess chamber 22.

In either case, the processes conducted within process chamber 22 mayinclude single or multi-phase operations. More specifically, theprocesses conducted within process chamber 22 may employ a single phaseoperation, such as one primarily comprising a liquid, a gas, or aplasma. Alternatively, the processes conducted within process chamber 22may use a multi-phase operation, having a combination of liquid, gas,and/or plasma. In some embodiments, employing a single liquid phaseenvironment may offer a manner with which to control the pressure withinprocess chamber 22. The benefits of controlling pressure within processchamber 22 is described in more detail below. In general, however,increasing the pressure within process chamber 22 will increase theboiling point of a solution used within the chamber and may consequentlyincrease the reaction rate of the process within process chamber 22.

A method for electrolessly depositing a layer upon a microelectronictopography in single liquid phase environment is illustrated in FIG. 5.In general, the method may include loading the microelectronictopography into an electroless deposition chamber and sealing thedeposition chamber to form an enclosed area about the topography asshown in steps 82 and 83, respectively. The method may continue to step84 in which the entirety of the enclosed area is filled with adeposition solution such that no gas is present. In particular, the stepof filling may include introducing the deposition solution at a firstinlet flow rate and narrowing one or more outlet passages of theelectroless deposition chamber such that a composite first dispensingflow rate of the deposition solution through the outlets is less thanthe first inlet flow rate. In general, the flow rates of the fluid inthe inlet passages and outlet passages may be controlled by a fluid flowcontroller coupled to process chamber 22. It is noted that the firstinlet flow rate may be introduced through one or more inlets of thechamber. Such a process of filling may pressurize the enclosed area to apressure between approximately 5 psi and approximately 100 psi,increasing the boiling point of the deposition solution. In someembodiments, the method may include heating the deposition solution to atemperature less than approximately 25% below the boiling point of thedeposition solution to increase a reaction rate of the depositionsolution with the microelectronic topography. Consequently, pressurizingthe enclosed area of the process chamber may, in some embodiments, aidin increasing the deposition rate of the process.

In any case, the method may, in some embodiments, include replenishingthe deposition solution within the enclosed area as shown in step 85.Such a step of replenishing may, in some embodiments, include wideningone or more outlet passages of the process chamber such that a compositesecond dispensing flow rate of the deposition solution through theoutlets is substantially equal to the first inlet flow rate of thedeposition solution. Alternatively, the step of replenishing may includedecreasing the first inlet flow rate of the deposition solution to asecond inlet flow rate that is substantially equal to the firstdispensing flow rate of the deposition solution through outlets of theprocess chamber. In yet other embodiments, the step of replenishing mayinclude decreasing the first inlet flow rate of the deposition solutionto the process chamber to a second inlet flow rate and widening one ormore of the outlet passages to a composite second dispensing flow rate,wherein the composite second dispensing flow rate is substantially equalto the second inlet flow rate.

An exemplary configuration of process chamber 22 adapted to expose amicroelectronic topography to a single phase process is illustrated inFIGS. 6 a-6 d. As noted above, process chamber 22 may be adapted toperform a succession of different process steps. As such, althoughprocess chamber 22 is shown in FIG. 6 a-6 d without any of the auxiliarycomponents described in reference to FIG. 1, the process chamber shownin FIG. 6 a-6 d may be coupled to such components. In particular, theprocess chamber 22 illustrated in FIGS. 6 a-6 d may be coupled to supplylines, exhaust lines, temperature and pressure gauges and controls,storage tanks, and a CPU unit. In addition or alternatively, the processchamber illustrated in FIG. 6 a-6 d may include a plurality of inputports, such as but not limited to shower element 92 and dispensing arm94. The exclusion of such components within FIGS. 6 a-6 d is merely tosimplify the illustration of the drawings and, therefore, does notnecessarily indicate the absence of such components. Consequently, theprocess chamber illustrated in FIG. 6 a-6 d is not necessarilyrestricted to processing a microelectronic topography solely with theuse of a reservoir as described in more detail below. Rather, thedescription of process chamber 22 in reference to FIGS. 6 a-6 d simplyoffers one method of a plurality of methods with which to treat atopography within the process chamber.

Substrate holder 48 is shown within process chamber 22 in FIG. 6 a-6 dto aid in describing the adaptations of the chamber. Such a substrateholder may be substantially similar to the substrate holder depicted inFIG. 1 and, therefore, may include similar components and adaptations ofthe holder as described above. As shown in FIG. 6 a, process chamber 22may include reservoir 170 arranged above substrate holder 48.Alternatively, reservoir 170 may be arranged below substrate holder 48.In such an embodiment, process chamber 22 may be adapted to have wafer Warranged “face down” for processing. In other words, substrate holder 48may be adapted to holder wafer W in a manner such that the side of thewafer to be treated is facing reservoir 170. In yet another embodiment,reservoir 170 and substrate holder 48 may be oriented perpendicular tothe arrangement shown in FIGS. 6 a-6 d. In particular, substrate holder48 may be oriented such that the upper surface of the substrate holderis parallel with the sidewalls of process chamber 22. In this manner,wafer W may be arranged vertically within process chamber 22. In such anembodiment, reservoir 170 may be arranged to the right or left ofsubstrate holder 48. Consequently, process chamber 22 may be adapted tomove reservoir 170 in a horizontal direction in such a case.

In any case, reservoir 170 may be adapted to hold a fluid for processinga microelectronic topography. In some cases, the fluid may be a singlephase fluid, such as a liquid or a gas. In other embodiments, however,reservoir 170 may be adapted to hold multi-phase fluids. In either case,process chamber 22 may be adapted to replenish the fluid withinreservoir 170 such that fluid may retain its processing properties. Forexample, in some cases process chamber 22 may include inlet 176 andoutlet 178 coupled to reservoir 170. In some embodiments, the fluid maybe recycled through such an inlet and outlet. In any case, thereplenishing of the fluid in reservoir 170 may be conducted prior to,during, or subsequent to a processing step of the chamber.

In some embodiments, process chamber 22 may be adapted to move reservoir170 relative to substrate holder 48 as noted by the bi-directional arrowin FIG. 6 a. In particular, process chamber 22 may include moveableshaft 171 to which reservoir 170 is attached, or more specifically,hatch 172 of reservoir 170 is attached. In some embodiments, processchamber 22 may be adapted to position reservoir 170 in contact withsubstrate holder 48 as shown in FIG. 6 b. In other embodiments, however,process chamber 22 may be adapted to position reservoir 170 upon amicroelectronic topography residing on substrate holder 48. In eithercase, the adaptation of process chamber 22 to move reservoir 170 towardsubstrate holder 48 may allow an enclosed area to be formed about aportion of substrate holder 48, particularly in an area in which amicroelectronic topography may be arranged. In this manner, processchamber 22 may be adapted to position reservoir 170 proximate tosubstrate holder 48 such that a fluid stored in reservoir 170 may beused to process a microelectronic topography arranged upon the substrateholder.

As shown in FIG. 6 b, process chamber 22 may be further adapted to raisehatch 172 of reservoir 170 as well as open valves 174 of reservoir 170upon positioning the reservoir proximate to substrate holder 48.Consequently, the transition between FIGS. 6 a and 6 b may illustratethe movement of reservoir 170 as a whole toward substrate holder 48 andFIG. 6 b may illustrate the raising of hatch 172 and the opening ofvalves 174. In an alternative embodiment, hatch 172 may be adapted toopen rather than be raised. In particular, hatch 172 may include ashutter window aligned with the region of substrate holder 48 upon whicha wafer may be arranged. In any case, raising and/or opening hatch 172may allow a microelectronic topography arranged upon substrate holder 48to be exposed to fluid stored within reservoir 170, allowing treatmentof the microelectronic topography to start. Opening valves 174 mayadditionally or alternatively serve to expose a wafer to a fluid storedwithin reservoir 170. In general, the treatment process conducted withinprocess chamber 22 may include any process step of a fabricationsequence for a microelectronic device, including but not limited toetching, depositing, cleaning, activating, and/or drying. In someembodiments, the configuration of process chamber 22 may be particularlyadvantageous for an electroless deposition process.

In any case, hatch 172 may be formed from a polymer or any othermaterial used in microelectronic fabrication for reservoirs. In someembodiments, hatch 172 may made of a permeable material, such assynthetic membranes, such that ions within the fluid of reservoir 170may be distributed upon wafer W when hatch 172 is aligned with the baseof reservoir 170. Such a configuration may be particularly advantageousfor embodiments in which an electroless deposition process is conductedwithin process chamber 22. In some embodiments, hatch 172 may furtherinclude a polymer shutter window to prevent the distribution of ionsthrough the permeable material for processes conducted prior to orsubsequent to the electroless deposition process. In any case, hatch 172may be configured to have a length (e.g. a diameter) which allows asubstantial portion of a wafer arranged upon substrate holder 48 to beexposed to a fluid stored within reservoir 170. For example, in somecases, latch 172 may include a length which is substantially similar tothe diameter of a wafer as shown in FIG. 6 b. In other embodiments,however, latch 172 may have a length which is longer than the diameterof a wafer. In general, hatch 172 may have a plan view of any shape,including but not limited to circles and rectangles.

Prior to the raising hatch 172, the hatch may be detached from thesidewalls of reservoir 170 to allow the reservoir to remain proximate tosubstrate holder 48. In other cases, however, process chamber 22 may notbe adapted to raise hatch 172 or hatch 172 may be omitted from reservoir170. In such an embodiment, exposing fluid stored within reservoir 170to a microelectronic topography arranged upon substrate holder 48 may besolely achieved by opening valves 174. In yet other embodiments, processchamber 22 may not be adapted to open valves or valves 174 may beomitted from reservoir 170. In such a case, exposing fluid stored withinreservoir 170 to a microelectronic topography arranged upon substrateholder 48 may be solely achieved by raising hatch 172. Consequently, insome cases, process chamber 22 may be adapted to only raise hatch 172 oropen valves 172. In addition, although FIGS. 6 a-6 d illustratereservoir 170 including two valves, any number of valves may be includedwithin reservoir 170. Consequently, process chamber 22 is not restrictedto the configurations depicted in FIGS. 6 a-6 d.

As shown in FIG. 6 c, process chamber 22 may be adapted to continueraising hatch 172. In general, hatch 172 may be raised to any positionwithin reservoir 170. In some embodiments, it may be particularlyadvantageous to raise hatch 172 to a level mid-way within reservoir 170when hatch 172 is used to mix and/or agitate the fluid within thereservoir. In this manner, hatch 172 may be sufficiently distanced fromthe chamber walls of reservoir 170. In other cases, however, hatch 172may be raised to a level other than the mid-way position withinreservoir 170 without disturbing the sidewalls of the reservoir. In anycase, process chamber 22 may be adapted to agitate the fluid storedwithin reservoir 170. In particular, process chamber 22 may be adaptedto cause a sufficient amount of motion within reservoir 170 to preventthe accumulation of bubbles upon the microelectronic topography. In someembodiments, the adaptation to agitate the fluid may include anadaptation to rotate hatch 172. More specifically, process chamber 22may be adapted to turn shaft 171 such that hatch 172 attached theretomay be rotated. It is noted that other agitation mechanisms known inmicroelectronic fabrication or described herein may also oralternatively be used to agitate the fluid within reservoir 170,depending on the design specifications of the process chamber. In anycase, the agitation of the fluid within reservoir 170 may be conductedduring or subsequent to raising hatch 172.

Upon completion of the fabrication process step, hatch 172 may belowered back down to be in alignment with the base of reservoir 170 asshown in FIG. 6 d. In particular, process chamber 22 may be adapted tomove shaft 171 such that hatch 172 is proximate to substrate holder 48.Upon lowering hatch 172, fluid may be forced back through valves 174 asshown in FIG. 6 d. In this manner, reservoir 170 may retain the processfluid used to treat the microelectronic topography. Subsequent tolowering hatch 172 to be in alignment with the base of reservoir 170,hatch 172 may be coupled to the base and reservoir 170 may be raised toa level spaced above substrate holder 48. In this manner, the waferarranged upon substrate holder 48 may be removed from process chamber 22and a new wafer may be loaded therein.

Returning to FIG. 1, system 20 may include auxiliary equipment tofurther enhance the introduction of fluids to process chamber 22. Forexample, in some embodiments, system 20 may be adapted to control theflow rate and time at which a fluid is supplied to process chamber 22.As such, supply lines 74, 75, 76 a, 76 b, 76 c, 78 and 80 may includesolenoid valves in some cases. Operation of the solenoid valves as wellas other components within system 20 may be controlled through centralprocessing unit (CPU) 106 as described in more detail below. In someembodiments, system 20 may include heaters, coolers, and thermocouplesfor regulating the temperature of a fluid introduced into processchamber 22. In fact, it may be particularly advantageous to regulate thetemperature of a solution used for an electroless deposition process.Typically, the deposition rate of an electrolessly deposited materialincreases with increases in temperature. Some electroless depositionsolutions, however, tend to decompose at or near their boiling point,causing a material to be non-uniformly deposited or not deposited atall. As such, supply line 74 may, in some embodiments, includetemperature control unit 86, which is adapted to heat and monitor thetemperature of the solution routed for reservoir 70. In some cases,process chamber 22 may further include temperature sensor 87 installedin solution return line 88 and communicably coupled to temperaturecontrol unit 86. In yet other cases, reservoir 70 and/or supply line 75may additionally or alternatively include a temperature sensor or atemperature control unit.

In general, the temperature of an electroless deposition solution duringprocessing may be between approximately 16° C. and approximately 120° C.However, in some cases, an electroless deposition solution may bemaintained at a temperature, which is approximately 25% or less belowits boiling temperature. Maintaining an electroless deposition solutionat such a temperature may maximize the deposition rate of the process insome embodiments. In yet other embodiments, an electroless depositionsolution may be maintained at room temperature in order to maximize theuniformity of the deposition. It is noted that although theaforementioned temperature controls are discussed in reference tomonitoring and heating a supply line or tank for an electrolessdeposition solution, the control devices may be used for regulating thetemperature of any fluid introduced into process chamber 22. As such,process chamber 22 may, in some embodiments, additionally oralternatively include temperature control devices within auxiliary tanks72 a, 72 b, 72 c and/or supply lines 76 a, 76 b, 76 c, 78, 80.

In some embodiments, system 20 may additionally or alternatively beadapted to heat and/or cool substrate holder 48. Such an adaptation maybe particularly advantageous for improving the deposition rate anduniformity of an electroless deposition process. For example, heatingsubstrate holder 48 and, thus, the wafer residing thereon, during adeposition process may advantageously increase the deposition rate of aprocess. In such an embodiment, the relatively high deposition rate maybe realized while the electroless deposition solution is supplied toprocess chamber 22 at a relatively low temperature, preventing thesolution from decomposing. In addition, an adaptation to cool asubstrate may offer a manner with which to immediately terminate adeposition process and, thus, allow for more control over the amountdeposited upon the substrate. For an efficient deposition of metals froman electroless deposition solution, the temperature on the surface ofthe wafer supported upon substrate holder 48 may be maintained betweenapproximately 16° C. and approximately 120° C. Larger or smallersubstrate temperatures, however, may be used, depending on the materialto be deposited.

In some embodiments, the adaptation to heat and/or cool a wafer may beincorporated within substrate holder 48. In particular, an electricheater and/or a circulation-fluid cooler may be built into the body ofsubstrate holder 48. In yet other embodiments, substrate holder 48 mayinclude a Peltier-type cooler/heater which is adapted to serve the dualroles of heating and cooling the substrate holder. In particular, thePeltier-type cooler/heater may include a package of two semiconductorplates that operate on the principle of generating heat when currentflows in one direction and absorbing heat when current flows in theopposite direction. Descriptions and illustrations of mechanisms used toheat and/or cool a substrate holder may be found in U.S. patentapplication Ser. No. 10/242,331 and is incorporated by reference as iffully set forth herein.

As noted above, the components lining chamber walls 23, cover 24, andbase 25 may be adapted to hermetically seal process chamber.Consequently, process chamber 22 may be pressurized in some embodiments.In some cases, it may be advantageous to regulate the pressure withinprocess chamber 22 and, therefore, in some embodiments, process chamber22 may include pressure sensor 89. Although pressure sensor 89 is shownarranged within supply line 80 in FIG. 1, pressure sensor 89 may belocated within any other supply line of system 20 or within processchamber 22. In some embodiments, it may be advantageous to pressurizeprocess chamber 22 to a predetermined value through the use of supplylines 74, 75, 76 a, 76 b, 76 c, 78, 80, and/or outlets of the processchamber. In particular, it may be advantageous to pressurize processchamber 22 to a level, such as between approximately 5 psi andapproximately 100 psi, or more specifically, to approximately 50 psi.Larger or smaller values of pressure may be generated within processchamber 22, however, depending on the process parameters of the devicebeing fabricated and the operational parameters of system 20. Ingeneral, increasing the pressure within process chamber 22 may increasethe boiling point of the fluids supplied to the chamber duringprocessing of a wafer in the chamber. As noted above, the depositionrate of an electroless deposition solution typically increases withincreases in temperature, but tends to decompose at or near its boilingpoint, causing a material to be non-uniformly deposited or not depositedat all. As such, increasing the pressure within process chamber 22 mayadvantageously allow a material to be deposited faster and, in somecases, more uniformly.

In addition to increasing the boiling point of a processing fluid,increasing the pressure within process chamber 22 may advantageouslyminimize the generation of bubbles upon a wafer during processing. Inparticular, increasing the pressure within process chamber 22 maydecrease the generation of hydrogen atoms within the reaction of theelectroless deposition process, thereby decreasing the number of bubblesto accumulate upon the wafer being processed within the chamber. Asnoted above, the accumulation of bubbles upon a wafer surface duringprocessing may undesirably cause a microelectronic topography to beprocessed non-uniformly, potentially producing device features withdimensions out of the design specification of the device. In some cases,a microelectronic topography may be wetted with a fluid comprising asurfactant prior to exposing the topography to the fluids with which toprocess the topography to reduce the accumulation of bubbles on thesurface of the topography. For example, a microelectronic topography maybe wetted with a fluid comprising polyethylene glycol such thatunwettable portions of the topography may be transposed into portionsadapted to be wetted by subsequent processing fluids. Increasing thewettability of the microelectronic surface may advantageously reduce thegeneration and accumulation of bubbles upon the microelectronictopography during processing.

Another manner with which to minimize the accumulation bubbles on awafer during processing is to agitate the fluid used to process thewafer. Consequently, in some embodiments, process chamber 22 may includea means with which to agitate fluids supplied to the chamber. Forexample, process chamber 22 may include means 90 arranged within processchamber 22 as shown in FIG. 1. In particular, means 90 may be arrangedat a level above substrate holder 48. Alternatively, means 90 may bearranged at a level below substrate holder 48. In yet other embodiments,means 90 may be coupled to substrate holder 48. In some cases, means 90may include a transducer adapted to provide acoustic waves to a fluidused to process a wafer within the chamber. For example, the transducermay be adapted to provide ultrasonic or megasonic waves. In either case,the transducer may be arranged such that the acoustic waves arepropagated parallel or perpendicular to a treating surface of the wafer.In yet other embodiments, the transducer may be arranged such that theacoustic waves are propagated at an angle between approximately 0° andapproximately 90° relative to a treating surface of the wafer. The“treating surface” of a wafer, as used herein, may refer to the surfaceof the wafer at which fluids are introduced to fabricate features uponthe wafer. Although means 90 is shown arranged within process chamber 92in FIG. 1, process chamber 22 may additionally or alternatively includea transducer within any of the supply lines coupled to process chamber22. In yet other embodiments, process chamber 22 may not include atransducer with which to provide acoustic waves.

In any case, means 90 may, in some embodiments, additionally oralternatively include a device configured to move across an enclosedregion of process chamber 22. More specifically, means 90 may include adevice configured to move across the region directly above substrateholder 48. In this manner, the device may be configured to move across awafer being processed within process chamber 22. In some embodiments,the device may be configured to come into contact with the wafer. Inother embodiments, however, the device may be configured to not comeinto contact with the wafer. In particular, the device may be configuredto traverse the enclosed region at a level spaced above the wafer whencontact with the device may cause damage to the wafer. In someembodiments, the device may be configured to distribute one or morefluids toward substrate holder 48 such that a wafer may be processed. Inthis manner, the device may serve as a fluid inlet to process chamber22. In some cases, it may be particularly advantageous for the device todeliver fluids at a rate sufficient to eliminate the “loading effect”during processing. The “loading effect,” as used herein, may refer tothe higher rate of consumption of active components within a fluid inhigh density areas of a wafer as compared to the rate of consumption inareas with a lower density of features. For example, sulfuric acid maybe consumed faster in a region comprising a high density of copperinterconnects as compared to a region of a wafer comprising a few or nocopper interconnects. In yet other cases, the device may not be adaptedto dispense a fluid, but rather, may simply be used to agitate the fluidabove substrate holder 48.

In any case, the device may include any mechanism which may cause asufficient amount of agitation with which to remove and/or prevent theaccumulation of bubbles on the surface of the underlying wafer. In apreferred embodiment, the adaptation to agitate may be sufficient tocause laminar agitation rather than turbulent agitation. Turbulentagitation may undesirably cause processing to be non-uniform across awafer, while laminar agitation may be sufficient to remove and/orprevent the accumulation of bubbles on the wafer surface and not affectthe uniformity of the process. As noted above, the device may beconfigured to dispense one or more fluids. Such an adaptation may beused to agitate the fluid above substrate holder 48 in some embodiments.Other manners for agitating the fluid, however, may additionally oralternatively be used. For example, in some embodiments, the device mayinclude a brush with a plurality of bristles to stir the fluid withinprocess chamber 22. Alternatively, the device may simply include asingle rod, block, or plate. In some embodiments, the device may includea propeller. In this manner, a high fluid flow rate may be induced aboutthe substrate surface without utilizing a complex system of highpressure pumps and tubing. Consequently, it is noted that the device mayinclude any design and may traverse at any speed sufficient to cause adisturbance with which to minimize the number of bubbles on a wafersurface. In yet other cases, however, process chamber 22 may not includesuch a device.

Regardless of whether means 90 includes the aforementioned device or atransducer, means 90 may offer a means of agitating a fluid withinprocess chamber 22 that is distinct from the inlets used to supply thefluid. As will be described in more detail below, fluids may beintroduced into process chamber 22 through either shower element 92,dispense arm 94, or any other inlet ports coupled to supply lines 74,75, 76 a, 76 b, 76 c, 78, and/or 80. As such, means 90 may offer amanner with which to agitate process fluids which are independent fromshower element 92, dispense arm 94, and/or any other inlet ports coupledto supply lines 74, 75, 76 a, 76 b, 76 c, 78, and/or 80. In someembodiments, however, process chamber 22 may not include means 90.

In any case, shower element 92, dispense arm 94, and/or the inlet portscoupled to supply lines 74, 75, 76 a, 76 b, 76 c, 78, and/or 80 mayadditionally or alternatively serve to agitate a process fluid arrangedwithin process chamber 22. More specifically, shower element 92,dispense arm 94, and/or the inlet ports coupled to supply lines 74, 75,76 a, 76 b, 76 c, 78, and/or 80 may, in some embodiments, be adapted tointroduce a fluid into process chamber 22 at a sufficient rate withwhich to agitate the fluid within the chamber. For example, in someembodiments, shower element 92, dispense arm 94, and/or the inlet portscoupled to supply lines 74, 75, 76 a, 76 b, 76 c, 78, and/or 80 may beadapted to introduce a fluid at a rate between approximately 0.01gallons per minute (gpm) and approximately 10 gpm, or more specifically,between approximately 0.1 gpm and approximately 10 gpm. However, largeror smaller flow rates may be used, depending on the process parametersof the device being fabricated and the operational parameters of system20. In addition or alternatively, shower element 92, dispense arm 94,and/or the inlet ports coupled to supply lines 74, 75, 76 a, 76 b, 76 c,78, and/or 80 may be adapted to pulse the introduction of a fluid intoprocess chamber 22. Such a pulsation may be at a frequency betweenapproximately 0.1 Hz and approximately 10 Hz, or more specifically,between approximately 1.0 Hz and approximately 10 Hz. Larger or smallerfrequencies may be used, however, depending on the process parameters ofthe device being fabricated and the operational parameters of system 20.

Regardless of the method used to agitate a fluid within process chamber22, the motion created within process chamber 22 is preferablysufficient to minimize the generation and/or accumulation of bubbles ona wafer surface. As noted above, reducing the number of bubbles upon awafer surface during treatment of the wafer may significantly improvethe uniformity of the treatment on the wafer surface. Consequently, theprocess of agitating a fluid may result in a wafer feature havingsubstantially uniform dimensions. For example, a deposition solutionused to deposit a layer upon a wafer may be agitated to create an amountof motion sufficient to form a layer having substantially uniformthickness across the wafer. Since an electroless deposited material maybe particularly susceptible to non-uniformity with the presence ofbubbles, process chamber may, in some cases, be specifically adapted toagitate a deposition solution supplied to the chamber. In particular,means 90, shower element 92, dispense arm 94, and/or the inlet portscoupled to supply lines 74, 75, 76 a, 76 b, 76 c, 78, and/or 80 may beprogrammed to use their agitation adaptations when a deposition solutionis being introduced into process chamber 22. In some cases, means 90,shower element 92, dispense arm 94, and/or the inlet ports coupled tosupply lines 74, 75, 76 a, 76 b, 76 c, 78, and/or 80 may be adapted toagitate other solutions associated with the fabrication of amicroelectronic device as well.

Consequently, a method for minimizing the accumulation of bubbles upon awafer during an electroless deposition process is provided herein. Sucha method is depicted in FIG. 7 and may include any or all of the processparameters listed for the components used to agitate a fluid withinprocess chamber 22 as described above. As shown in FIG. 7, the methodmay include step 95 in which a wafer is loaded into an electrolessdeposition chamber. In some embodiments, the wafer may be loaded suchthat the wafer is face-up in the electroless deposition chamber. Ingeneral, “face-up,” as used herein, may refer to the orientation of awafer having a surface to be treated facing upward, or morespecifically, facing the top of a chamber. In turn, “face-down,” as usedherein, may refer to the orientation of a wafer having a surface to betreated facing downward, or more specifically, facing the bottom of achamber. Such an orientation may advantageously reduce the accumulationof bubbles upon the wafer surface. The method depicted in FIG. 7 is not,however, restricted to loading a wafer in such an orientation. As such,in other embodiments, the method may include loading the waferface-down. In such an embodiment, the process steps of pressurizing thechamber and/or agitating the process fluid, as described in more detailbelow, may serve to minimize the generation and accumulation of bubbleson the wafer surface.

In any case, the method may further include sealing the electrolessdeposition chamber to form an enclosed area about the wafer as shown instep 96. As noted above, such a sealing process may serve to pressurizea chamber. In some embodiments, however, the method may includepressurizing the enclosed area to a predetermined value as noted in step97. Such a predetermined value may be between approximately 5 psi andapproximately 100 psi, or more specifically, approximately 50 psi.Larger or smaller pressures may be generated, however, depending on theprocess parameters of the device being fabricated and the operationalparameters of system 20. In general, pressurizing the chamber to suchvalues may be accomplished by introducing fluids into the chamber andrestricting flow from the outlets of the chamber.

As noted above, pressurizing the chamber may advantageously reduce thegeneration and accumulation of bubbles on a wafer surface duringprocessing. As such, the steps of agitating the deposition solution andpressurizing the chamber may collectively reduce the amount of bubblesformed upon the wafer during the electroless deposition process. Inembodiments in which the wafer is loaded face-up, the method maycollectively offer three manners with which to reduce the amount ofbubbles formed upon the wafer during the electroless deposition process.In yet other embodiments, step 97 may be omitted from the methoddepicted in FIG. 7. In such an embodiment, the step of agitating mayexclusively serve to minimize the generation and accumulation of bubblesupon a wafer surface or may collectively serve such a function when thewafer loaded face-up and/or the wafer is prewetted as described inreference to step 97 a.

As shown in FIG. 7, the method may, in some embodiments, include step 97a in which the wafer is prewetted. Such a step may include introducing asubstantially neutral solution to the wafer such that dry spots or areaswith surface irregularities may be wetted to prevent the formation ofbubbles at such locations. In yet other embodiments, step 97 a may beomitted from the method. In any case, the method may further includesupplying a deposition solution to the enclosed area and agitating thedeposition solution as shown in steps 98 and 99, respectively. As notedabove, agitating step 99 preferably includes creating a sufficientamount of motion such that a layer having a substantially uniformthickness may be fabricated. Such a step may include using any of themeans for agitating a solution described above, including exposing thedeposition solution to acoustic waves, moving a device above and acrossa wafer, and/or distributing fluid continuously or in a pulsing sequencethrough any of the fluid inlets coupled to the chamber.

As noted above, fluids may be supplied to process chamber 22 throughshower element 92, dispense arm 94, means 90 and/or any of the inletports coupled to supply 74, 75, 76 a, 76 b, 76 c, 78, and/or 80. Thefluids may include those used for any fabrication process of amicroelectronic topography, including processes used for depositing,etching, cleaning, polishing, and/or drying a topography. In someembodiments, the fluids may be further used to clean and/or dry theinterior of process chamber 22. In particular, the inlet ports ofprocess chamber 22 may be adapted to distribute fluids such that theinterior surfaces of dry cover 24, sidewalls 23, and base 25 may becleaned and/or dried. In some cases, the chamber walls may be cleanedand/or dried while a topography arranged upon substrate holder 48 iscleaned and/or dried, reducing production down time to clean thechamber. In any case, the fluid inlets of process chamber 22 may beadapted to supply one or more fluids to the process chamber. Inparticular, the fluid inlets may be adapted to supply fluidssimultaneously or sequentially into process chamber 22.

In general, shower element 92 may be adapted to dispense a fluid as aspray extending across nearly the entire wafer. In this manner, thefluid may be dispensed across the entire wafer. As shown in FIG. 1,shower element 92 may be centrally positioned above substrate holder 48.Such a position of shower element 92 along with rotation of substrateholder 48 may insure a uniform distribution of fluid across a wafer,although a fluid can be uniformly distributed with shower element 92 inother locations as well. As such, process chamber 22 is not restrictedto having shower element 92 in the location depicted in FIG. 1. Inparticular, shower element 92 may be alternatively positioned at otherlocations within process chamber 22. “Spray,” as used herein, may referto a stream of finely divided streams, particles, or droplets. As such,shower element 92 may include one or more nozzles adapted to distributea fluid at a high enough pressure such that a spray is generated. Inaddition or alternatively, shower element 92 may include a disc uponwhich fluid is introduced and distributed over the sides. In eithercase, shower element 92 may be alternatively adapted to distribute afluid such that its stream is not divided into separate streams ordroplets.

As noted above, process chamber 22 may further or alternatively includedispensing arm 94. FIG. 1 shows dispensing arm 94 extending above aportion of substrate holder 48. In other embodiments, however,dispensing arm 94 may extend across the entire wafer. In either case,the fluid introduced through dispensing arm 94 may be uniformlydistributed across a wafer by rotating the wafer. In yet otherembodiments, dispensing arm 94 may be configured to distribute across anentirety of a wafer without rotating the wafer. In yet other cases,dispensing arm 94 may be configured to distribute a fluid upon a portionof the wafer. In any case, dispensing arm 94 may include one or moreoutlets with which to distribute a fluid across a wafer. In particular,dispensing arm 94 may include a plurality of outlets spaced along thearm and directed toward substrate holder 48. Alternatively, dispensingarm 94 may include a single outlet, near the end of the arm extendingabove substrate holder 48, for example. In either case, the outletswithin dispensing arm 94 may, in some embodiments, include nozzles suchthat a fluid may be introduced as a spray from the arm. In yet otherembodiments, the outlets may include openings which allow the fluid tobe introduced upon a wafer in a non-spray manner.

In some cases, dispensing arm 94 may be configured to move. Morespecifically, dispensing arm 94 may be configured to move from aposition above substrate holder 48 to a location adjacent to thesubstrate holder. For example, one end of dispensing arm 94 may beconnected to a respective rotary drive mechanism arranged adjacent tosubstrate holder 48 such that the arm may pivot at such a location. Suchan adaptation may allow the wafer to be more easily loaded into processchamber 22. More specifically, the moveable adaptation of dispensing arm94 may allow a wafer to be loaded into process chamber 22 without beingdamaged. In addition, such a moveable adaptation may allow dispensingarm 94 to deliver a fluid to a specific area of the wafer, therebyproviding variable exposure of a process fluid to the wafer.

In some embodiments, shower element 92 may be used to distribute adeposition solution, while dispensing arm 94 may be used to distributefluids for processes prior to or subsequent to a deposition process. Forexample, in some cases, dispensing arm 94 may be used to distributefluids for activation, cleaning, rinsing and/or drying a wafer. Theprocess chamber described herein, however, is not restricted to such aconfiguration. In particular, shower element 92 and dispensing arm 94may be used to distribute any fluid for any process used to fabricate amicroelectronic device. In addition, shower element 92 and dispensingarm 94 may be used to distribute fluids for the same process and,therefore, may distribute fluids simultaneously in some cases.Furthermore, one or both of shower element 92 and dispensing arm 94 maybe used for distributing fluids for all processes conducted in processchamber 22. In some cases, fluids may be supplied to process chamber 22by inlets other than by shower element 92 and dispensing arm 94. Inparticular, fluids may be supplied to process chamber 22 by any inletcoupled to a fluid supply line. In general, the inlets may be positionedat any location within process chamber 22. For example, process chamber22 may include, in some embodiments, fluid inlets arranged along thesidewall 23 or base 25 of the process chamber. In this manner, processchamber 22 may be adapted to introduce fluids above a wafer, from belowa wafer, or in between wafers when multiple wafers are processed withinthe process chamber.

In some embodiments, process chamber 22 may include fluid inlet 100positioned below substrate holder 48 as shown in FIG. 1. In some cases,inlet 100 may be configured such that fluid from the inlet is projectedonto the wafer. More specifically, inlet 100 may be configured to directfluid toward a region just above substrate holder 48, such that thefluid is indirectly projected onto the wafer. An “indirect projection offluid”, as used herein, may refer to a projection of fluid which is notcast in a straight line toward its target. The target in process chamber22, for example, may be a wafer arranged upon substrate holder 48. Ingeneral, the adaptation of inlet 100 to indirectly project a fluidtoward substrate holder 48 may include positioning the inlet to projectthe fluid at an angle less than 90° and greater than 0° with respect tochamber wall 23. In addition, the flow rate of the fluid is preferablyhigh enough to project the fluid above substrate holder 48. In somecases, a fluid may be projected from inlet 100 at a flow rate sufficientto have the crest of the projection between cover 24 and substrateholder 48. In this manner, the fluid may be distributed upon a waferarranged upon the substrate holder 48. In other embodiments, however, afluid may be projected from inlet 100 at a flow rate sufficient to hitcover 24 and reflect down to a wafer arranged upon substrate holder 48.

In either case, the flow rate and angle at which the fluid is projectedfrom inlet 100 may be configured to distribute the fluid in a specificarea of the wafer. For example, in some cases, the flow rate and angleat which the fluid is projected from inlet 100 may be configured todispense the fluid along the edge of the wafer, the center of the wafer,or any other specific location of the wafer. In some embodiments, system20 may be adapted to adjust the flow rate and angle at which the fluidis projected from inlet 100 such that the locations the fluid isdispensed varies. In this manner, the fluid may be uniformly distributedacross the wafer. In other embodiments, system 20 may additionally oralternatively include a plurality of fluid inlets spatially arrangedaround substrate holder 48 such that the fluid is distributed uniformlyacross the wafer. An example of such a configuration of inlets isdescribed in more detail below in reference to FIGS. 8 a and 8 b. In yetother cases, system 20 may be additionally or alternatively adapted torotate a wafer such that the fluid may be evenly distributed across thewafer. Alternatively, however, system 20 may not be adapted to rotate awafer.

Although inlet 100 is described as being positioned below substrateholder 48, inlet 100 is not restricted to such a location. On thecontrary, inlet 100 may be positioned at any location within processchamber 22. In this manner, process chamber 22 may include other inletswhich are adapted to indirectly project a fluid upon a wafer,independent of where they are located within process chamber 22. In yetother embodiments, inlet 100 may not be configured to indirectly projecta fluid upon a wafer. Rather, inlet 100 may simply be used to introducea fluid to the enclosed area of process chamber 22. Such a configurationmay be particularly advantageous in embodiments in which a bath ofsolution is maintained with process chamber 22 during processing.

Turning to FIGS. 8 a and 8 b, an exemplary arrangement of inlets withwhich to supply one or more fluids to process chamber 22 is shown. Inparticular, FIGS. 8 a and 8 b show a top view of process chamber 22taken along line AA in FIG. 1 with wafer W is secured to substrateholder 48 via clamping jaw 58. As shown in FIGS. 8 a and 8 b, processchamber 22 may, in some embodiments, include a plurality of inlets 160 aand 160 b configured to distribute one or more fluids into the processchamber. In some cases, the distribution of fluids from inlets 160 a and160 b may be projected to central portion 162 of wafer W as shown by thedotted lines in FIG. 8 a. Alternatively, the distribution of fluids frominlets 160 a and 160 b may be projected to a different or a plurality ofdifferent portions of wafer W. For example, fluids may be projected atan angle from inlets 160 a and 160 b to distribute the fluids to portion164 of wafer W as shown in FIG. 8 b. Such an adaptation mayadvantageously allow fluids to be distributed to a larger surface areaof wafer W from inlets 160 a and 160 b. In some cases, system 20 may beadapted to adjust the angle and flow rate of a fluid through inlets 160a and 160 b such that the distribution of fluids across wafer W mayvary. As a result, the distribution of fluids across wafer W may beadapted to be substantially uniform in some embodiments. As noted above,substrate holder 48 may be additionally adapted to rotate to furtherenhance the distribution of fluids across wafer W.

In general, inlets 160 a and 160 b may be arranged about substrateholder 48 such that the one or more fluids may be dispensed upon waferW. For example, inlets 160 a and 160 b may be arranged circumferentiallyaround substrate holder 48. In some embodiments, the arrangement ofinlets 160 a and 160 b may be uniform as shown in FIG. 7. In otherembodiments, however, the arrangement of inlets 160 a and 160 b may benot be uniform. In either case, inlets 160 a and 160 b may be arrangedbelow, above, and/or at the approximately the same level as the uppersurface of substrate holder 48. In this manner, inlets 160 a and 160 bmay, in some embodiments, include a similar configuration as inlet 100.In yet other embodiments, inlets 160 a and 160 b may be configured toproject one or more fluids directly upon wafer W.

In some cases, system 20 may be adapted to introduce different fluidsinto process chamber 22 through inlets 160 a and 160 b, respectively. Inthis manner, mixing fluids into a solution may be averted until thefluids are on the wafer. Such an adaptation may be particularlyadvantageous when using deposition solutions that quickly decompose. Forexample, the deposition of copper using electroless techniques sometimesincludes mixing a reducing agent and with a metal ion solution. Themixture of the fluids tends to quickly decompose, limiting thedeposition efficiency of the solution. As a consequence, the depositionsolution may need to be replenished often, if not continuously. Theadaptation of including plurality of inlets 160 a and 160 b mayadvantageously allow the fluids to mix at the surface of the wafer,increasing the life of the deposition solution. As a result, fluidconsumption may be reduced, decreasing the overall process costs offabricating a device with such a layer.

As shown in FIGS. 8 a and 8 b, inlets 160 a and 160 b may bealternatively spaced about substrate holder 48. Such an arrangement mayadvantageously reduce the amount of interaction between two fluids of asolution before combining them at the surface of a wafer. In otherembodiments, however, limiting the interaction of two fluids beforecombining them at the surface of a wafer may be accomplished byarranging inlets 160 a circumferentially along one side of substrateholder 48 and inlets 160 b circumferentially along the other side ofsubstrate holder 48. It is understood that other arrangements of inlets160 a and 160 b used to minimize the interaction of fluids before beingcombined at the surface of a wafer may be included within processchamber 22 as well.

In general, fluids supplied to process chamber 22 and used to process awafer residing upon substrate holder 48 may be removed through exhaustports of the chamber. For example, process fluids may be removed throughoutlets 88 and/or 102. Although outlets 88 and 102 are shown arrangedalong the bottom of process chamber 22, the outlets may be arrangedalong other portions of process chamber 22 as well or alternatively. Inaddition, process chamber 22 is not restricted to having two outletports. On the contrary, process chamber 22 may include any number ofoutlet ports. In some embodiments, the outlet ports may discharge thefluids to a waste stream to be disposed. In other embodiments, however,one or more of the outlet ports may serve to recycle the process fluidback to its respective storage tank. For example, outlet 88 may serve toreturn an electroless deposition solution back to reservoir 70. In thismanner, the deposition solution may be reused such that material anddisposal costs may be minimized. In some cases, outlet 88 may includefilter 103 such that reservoir 70 is not contaminated with particlesremoved from process chamber 22.

Since the elemental composition of a process fluid may directly affectthe reaction rate and uniformity of treating a microelectronictopography, process fluids may need to be analyzed and adjusted prior tobeing supplied to process chamber 22. As such, system 20 may includeanalytical test equipment 104 for monitoring fluids used within processchamber 22. In general, analytical test equipment 104 may be usedmeasure the concentration of elements within the process fluid. In thismanner, it can be determined whether the process fluid is inspecification or if the process fluid needs to be adjusted. Theinclusion of analytical test equipment 104 may be particularlyadvantageous when system is configured to recycle one or more fluidsback to their storage tanks. In general, processing a wafer may consumesome of the elements contained within the fluid used to process thewafer. Consequently, it may be advantageous to be able to monitor theconcentration of elements with a process fluid such that the fluid mayhave the proper composition prior to being supplied to process chamber22. In any case, analytical test equipment 104 may, in some embodiments,be coupled to supply line 75, as shown in FIG. 1, such that the processfluid may be analyzed directly before being supplied to process chamber22. In yet other embodiments, analytical test equipment 104 may beadditionally or alternatively coupled to supply line 75, reservoir 70,and/or outlet 88.

In general, analytical test equipment 104 may be adapted to measure theconcentration of one or more elements. In some embodiments, however, itmay be advantageous to have analytical test equipment 104 adapted toanalyze four or more components. For example, embodiments in whichprocess chamber 22 is used for a plurality of processes, such as theprocesses conducted prior to, during, and/or subsequent to anelectroless deposition process, the adaptation of being able to measurethe concentration of at least four components may be advantageous sincethe fluids used for the different process steps may have differentcompositions. In yet other embodiments, it may be advantageous to employanalytical test equipment with such an adaptation for processes whichuse solutions with a plurality of components. An exemplary process usinga solution with at least four components is described in more detailbelow in reference to FIG. 12 in which a four-element barrier layer isdeposited. In such an embodiment, it may be particularly advantageousfor analytical test equipment 104 to be configured to measure theconcentration of at least four components selected from the groupconsisting of boron compounds, chromium, cobalt, molybdenum, nickel,phosphorus compounds, rhenium, and tungsten.

Regardless of the number of components analytical test equipment 104 isadapted to analyze, system 20 may further include lines with which toadjust the composition of a process fluid. Such lines may be coupled tosupply lines 74 and 75, reservoir 70, and/or outlets 88 and 102. In someembodiments, analytical test equipment 104 may be adapted to analyze theamount of hazardous components discharged from process chamber 22through outlet 102. In this manner, the amount of agent needed toneutralize the hazardous components after being discharged may beoptimized.

In some embodiments, control of system 20 and its components may beexecuted through central processing unit (CPU) 106. For instance, CPU106 may include a carrier medium with program instructions for managingthe use of solenoid valves on supply lines supply 74, 75, 76 a, 76 b, 76c, 78, 80 and/or outlets 88 and/or 102 such that fluids may beintroduced and/or discharged for a predetermined sequence and, in somecases, for a predetermined amount of time. For example, upon completionof an electroless deposition process, CPU 106 may include programinstruction with which to discontinue the supply of fluid from supplylines 74 and 75. Subsequently, CPU 106 may send a command to supplydeionized water, for example, from supply line 78, or the supply ofanother treatment or neutralization solution. In some cases, CPU 106 mayalso send commands to regulate the flow of fluid through the outletports of process chamber 22 in between or during the discontinuation andsupply commands of the inlet ports.

In any case, CPU 106 may further include program instructions forcontrolling the pressure within process chamber 22 as well as thetemperature of substrate holder 48 and fluids introduced into processchamber 22. In some cases, CPU 106 may further include programinstructions for monitoring concentrations of solution elements withinsupply lines supply 74, 75, 76 a, 76 b, 76 c, 78, 80, reservoir 70,and/or solution feed back line 88. In such an embodiment, CPU 106 mayinclude program instructions for adjusting compositions of the solutionelements based upon the analysis performed by analytical test equipment104. In order for CPU 106 to control the components of system 20, CPU106 may be coupled to the components. Such individual connections to thecomponents, however, are not illustrated FIG. 1 to simplify theillustration of the system. Rather, CPU 106 is shown coupled to processchamber 22 by a dotted line to show a general connection to the chamberand the other components included within system 20.

As shown in FIG. 1, process chamber 22 is generally configured to form asingle enclosed area about substrate holder 48 for processing amicroelectronic topography. An alternative configuration for processchamber 22, however, may be adapted to form multiple enclosed areasabout substrate holder 48. An illustration of such an alternativeconfiguration is illustrated in FIGS. 9 a-9 c. In particular, FIGS. 9a-9 c illustrates process chamber 22 adapted to form two differentenclosed areas about a microelectronic topography. As noted above,process chamber 22 may be adapted to perform a succession of differentprocess steps. As such, although process chamber 22 is shown in FIGS. 9a-9 c without any of the auxiliary components described in reference toFIG. 1, the process chamber shown in FIGS. 9 a-9 c may be coupled tosuch components. In particular, the process chamber 22 illustrated inFIGS. 9 a-9 c may be coupled to supply lines, exhaust lines, temperatureand pressure gauges and controls, storage tanks, and a CPU unit.

Furthermore, the process chamber depicted in FIGS. 9 a-9 c may includeauxiliary equipment attached thereto. In particular, the process chambershown in FIGS. 9 a-9 c may, in some embodiments, include a gate arrangedalong a chamber wall and/or a cover of the chamber. In addition oralternatively, the process chamber illustrated in FIGS. 9 a-9 c mayinclude a plurality of input ports, such as but not limited to showerelement 92 and dispensing arm 94. The exclusion of input ports and agate within FIGS. 9 a-9 c is merely to simplify the illustration of thedrawings and, therefore, does not necessarily indicate the absence ofsuch components. Substrate holder 48, however, is shown within processchamber 22 in FIGS. 9 a-9 c to aid in describing the adaptations of thechamber. Such a substrate holder may be substantially similar to thesubstrate holder depicted in FIG. 1 and, therefore, may include similarcomponents and adaptations of the holder as described above.

In general, process chamber 22 may be adapted to form a first enclosedarea about and including substrate holder 48 as well as a second,smaller enclosed area about and including the substrate holder as shownin FIGS. 9 b and 9 c, respectively. FIG. 9 a, on the other hand,illustrates process chamber 22 during the loading of a wafer, prior tothe formation of the first and second enclosed regions. In someembodiments, the adaptation of process chamber 22 to form the first andsecond enclosed regions may include an outer set of portions and aninner set of portions configured to couple with each other andrespectively form the first and second enclosed regions. In particular,process chamber 22 may include upper outer portion 107 and lower outerportion 108 configured to form an enclosed region about substrate holder48. In general, the first enclosed region formed by coupling outerportions 107 and 108 may include everything within the interior of theouter portions, including inner portions 109 and 110. In someembodiments, such a first enclosed region may include the entirety ofprocess chamber 22. In other embodiments, however, process chamber 22may include one or more casings surrounding outer portions 107 and 108.

In either case, process chamber 22 may further include upper innerportion 109 and lower inner portion 110 configured to form a secondenclosed region about substrate holder 48. Such a second enclosed regionmay solely include the portions of process chamber 22 interior to theinner portions and, therefore, is not as large as the first enclosedregion. In this manner, the configuration of process chamber 22 mayallow multiple regions to be enclosed during processing of a topography.In some embodiments, outer portions 107 and 108 and inner portions 109and 110 may include other configurations with which to form therespective enclosed regions within process chamber 22. For example, gate28 and chamber wall 23 may alternatively serve as outer portions ofprocess chamber 22 with which to form a first enclosed region aboutsubstrate holder 48. In addition or alternatively, inner portions 109and 110 may include a different configuration with which to form thesecond enclosed region about substrate holder 48. For example, lowerinner portion 110 may, in some embodiments, configured in a concaveshape. As such, process chamber 22 is not restricted to the referencesand configurations of outer portions 107 and 108 and inner portions 109and 110 depicted in FIGS. 9 a-9 c. Rather, process chamber 22 maygenerally include outer and inner portions with which to form at leasttwo different enclosed regions about a substrate holder.

In some embodiments, the system comprising process chamber 22 may beadapted to couple outer portions 107 and 108 prior to the succession ofthe different process steps performed within the process chamber. Inaddition, the system may be adapted to couple and uncouple innerportions 109 and 110 between the different process steps withoutuncoupling outer portions 107 and 108. For example, the system may beadapted to couple inner portions 109 and 110 prior to an electrolessdeposition process and uncouple the inner portions subsequent to theelectroless deposition process. The system may be additionally oralternatively adapted to couple inner portions 109 and 110 prior to andsubsequent to other processing steps as well, depending on thefabrication parameters of the wafer. In this manner, the system may beadapted to dispense different processing fluids into the first andsecond enclosed areas during different process steps. In some cases, thesystem may be additionally or alternatively adapted to uncouple outerportions 107 and 108 for a drying process of the microelectronictopography. In yet other cases, however, the system may be adapted tokeep outer portions 107 and 108 closed until all processing steps arecompleted. In such an embodiment, a drying process may be alternativelyconducted by injecting gas through an air nozzle or by opening theprocess chamber to ambient air by a means other than uncoupling outerportions 107 and 108, such as opening a gate attached to process chamber22. In yet other embodiments, the drying process may be conducted bydischarging fluids within process chamber 22, creating a low-pressurevacuum by which to dry the topography.

As shown in FIGS. 9 a-9 c, process chamber 22 may include outlet 111arranged within lower outer portion 108 exterior to lower inner portion110. In addition, process chamber 22 may include outlet 112 arrangedwithin lower inner portion 110. In some embodiments, process chamber 22may be adapted to prevent processing fluids in the first enclosed areafrom entering the outlet 112. For example, in some embodiments, processchamber 22 may include a means for spinning a microelectronic topographyarranged upon substrate holder 48. In particular, process chamber 22 maybe adapted to rotate a wafer at a fast enough rate to prevent processingfluids from entering outlet 112. In general, such a rate may be betweenapproximately 0 rpm and approximately 8000 rpm or, more specifically,between approximately 40 rpm and approximately 1200 rpm and may beconducted when inner portions 109 and 110 are not coupled together. Incontrast, process chamber 22 may or may not spin a microelectronictopography when inner portions 109 and 110 are coupled. Larger orsmaller rates of rotation may be used in either case, depending on thedesign specifications of the system and viscosity of the process fluidas described in more detail below.

In some cases, upper inner portion 109 may also be adapted to rotate. Inparticular, upper inner portion 109 may be configured to rotate whendecoupled from lower inner portion 110. Such an adaptation to rotate mayadvantageously allow solution residue from one or more processing stepsto be removed from the inner surface of upper inner portion 109. In thismanner, cross-contamination of fluids used for different processes maybe prevented. In general, upper inner portion 109 may be adapted torotate during any process step used to fabricate a microelectronicdevice. For example, upper inner portion 109 may be rotated during arinse and/or a drying cycle of the fabrication process. In any case, therotation of upper inner portion 109 and the wafer may be conductedsimultaneously or may be conducted independent of each other. Inaddition, system 20 may be adapted to rotate upper inner portion 109 andthe wafer in the same direction and/or different directions.

A method for processing a microelectronic topography using theconfiguration illustrated in FIGS. 9 a-9 c is outlined in the flowchartof FIG. 10. The method may include steps 113 in which a microelectronictopography is loaded into a process chamber. Such a loading step maycorrespond to FIG. 9 a of process chamber 22. As shown in FIG. 10, themethod may further include step 114 in which the process chamber isclosed to form a first enclosed area about the microelectronictopography. FIG. 9 b illustrates the formation of such a first enclosedregion. The formation of the first enclosed area may, in someembodiments, include moving a cover plate toward a base plate of theprocess chamber. In yet other embodiments, however, the formation of thefirst enclosed area may include moving the base plate toward the coverplate or moving the cover plate and base plate toward each other. Ineither case, the method may further include supplying a first set offluids to the first enclosed area to process the microelectronictopography in one or more process steps as shown in step 115.

The method may continue to step 116 in which a second, distinct enclosedarea is formed about the microelectronic topography subsequent to thestep of supplying the first set of fluids. FIG. 9 c illustrates theformation of such a second enclosed region. The second enclosed area maybe supplied with a second set of fluids to further process themicroelectronic topography in one or more other process steps as shownin step 117. In some embodiments, the first set of fluids may includefluids for preparing the microelectronic topography for an electrolessdeposition process and the second set of fluids may include a depositionsolution for the electroless deposition process. In such an embodiment,the method may include reforming the first enclosed area subsequent tothe step of supplying the second set of fluids and supplying a third setof fluids to the reformed first enclosed area to process themicroelectronic topography subsequent to the electroless depositionprocess as shown in steps 118 and 119, respectively. Alternatively, thefirst set of fluids may include a deposition solution for an electrolessdeposition process, and the second set of fluids may include fluids forprocessing the microelectronic topography subsequent to the electrolessdeposition process.

In any case, the method may further include spinning the microelectronictopography as noted in step 120. Such a spinning step may be conductedwhile the first and/or second set of fluids is supplied to the processchamber. As such, step 120 is shown extending from steps 115 and 117 bya dotted line. In some embodiments, spinning the microelectronictopography may be further conducted during the formation of the firstand/or second enclosed areas. In general, the rate at which to spin thetopography may depend on the material supplied to the process chamber.In particular, a relatively high spin rate may be needed for fluids witha relatively high viscosity, while a relatively lower spin rate may beneeded for fluids with a relatively low viscosity. As such, the spinrate of the topography when the first and second sets of fluids aresupplied to the process chamber may be similar or may be substantiallydifferent.

In any case, the microelectronic topography may generally be spun at arate between approximately 0 rpm and approximately 8000 rpm, or morespecifically between approximately 40 rpm and approximately 1200 rpm,depending on the viscosity of the fluid supplied to the process chamber.In some embodiments, the topography may be rotated at a sufficient rateto prevent fluids from entering a certain outlet as noted above. Inembodiments in which the first and second sets of fluids comprise asimilar viscosity, the microelectronic topography may be rotated at adifferent rate when the first set fluids are supplied to the processchamber than when the second set of fluids are supplied to the processchamber. For example, in some embodiments, the microelectronictopography may be spun at a rate between approximately 0 rpm andapproximately 20 rpm when the first set of fluids is supplied to theprocess chamber. In contrast, the microelectronic topography may be spunat a rate between approximately 40 rpm and approximately 300 rpm whenthe second set of fluids is supplied to the process chamber or viceversa.

As noted above, methods for processing a microelectronic topography isprovided herein. In particular, methods for forming a contact structureor a via within a dielectric layer are described below in reference toFIGS. 11-18. Although the process steps described in reference to FIGS.11-18 are provided in sequence to each other, the process steps are notnecessarily co-dependent. Consequently, the method described inreference to FIGS. 11-18 may be performed independent of each other. Inaddition, the topographies depicted in FIGS. 11-18 are not drawn toscale. In particular, the dimensions of the layers and structures mayvary from tens of angstroms to a few microns. As such, the methoddescribed herein is not restricted to forming a device having therelative dimensions of the layers and structures depicted in FIGS.11-19. In some embodiments, the process steps described in reference toFIGS. 11-18 may be conducted using the system and/or techniquesdescribed in reference to FIGS. 1-10. However, the process steps ofFIGS. 11-18 are not restricted to the use of such a system. Inparticular, the process steps described in reference to FIGS. 11-18 maybe either conducted within the same chamber or within differentchambers.

FIG. 11 depicts microelectronic topography 140 having trench 146 formedwithin dielectric layer 144, which in turn is formed upon underlyinglayer 142. In general, dielectric layer 144 may be an interleveldielectric layer and may serve as an insulating layer, etch stop layer,and/or a polishing stop layer. In any case, dielectric layer 144 mayhave a thickness between approximately 2,000 angstroms and approximately10,000 angstroms. Larger or smaller thicknesses of dielectric layer 144,however, may be appropriate depending on the semiconductor device beingformed. Dielectric layer 144 may include one or more of variousdielectric materials used in microelectronic fabrication. For example,dielectric layer 144 may include silicon dioxide (SiO₂),tetraethylorthosilicate glass (TEOS) based silicon dioxide, siliconnitride (Si_(x)N_(y)), silicon dioxide/silicon nitride/silicon dioxide(ONO), silicon carbide, carbon-doped SiO₂, or carbonated polymers.Alternatively, dielectric layer 144 may be formed from alow-permittivity (“low-k”) dielectric, generally known in the art as adielectric having a dielectric constant of less than about 3.5. Onelow-k dielectric in current use, which is believed to make a conformalfilm, is fluorine-doped silicon dioxide. In some cases, dielectric layer144 may be undoped. Alternatively, dielectric layer 144 may be doped toform, for example, low doped borophosphorus silicate glass (BPSG), lowdoped phosphorus silicate glass (PSG), or fluorinated silicate glass(FSG). Low doped BPSG may have a boron concentration of less thanapproximately 5% by weight. Low doped PSG may have a phosphorusconcentration of less than approximately 10% by weight, and morepreferably less than approximately 5% by weight.

In some cases, underlying layer 142 may be a silicon substrate and may,in some embodiments, be doped either n-type or p-type. Morespecifically, underlying layer 142 may be a monocrystalline siliconsubstrate or an epitaxial silicon layer grown on a monocrystallinesilicon substrate. In addition or alternatively, underlying layer 142may include a silicon on insulator (SOI) layer, which may be formed upona silicon wafer. In any case, the feature subsequently formed withintrench 146 may serve as a contact structure to portions of a siliconsubstrate in some embodiments. In other cases, however, underlying layer142 may include metallization and/or an interlevel dielectric of amicroelectronic topography. In such an embodiment, the featuresubsequently formed within trench 146 may serve as a via to underlyingportions of microelectronic topography 140. In yet other embodiments,the feature subsequently formed within trench 146 may serve as aninterconnect line or any other metallization feature of themicroelectronic topography.

In any case, trench 146 may be formed within dielectric layer 144 by alithography process known to those skilled in the art of microelectronicfabrication. In particular, a photoresist layer may be patterned upondielectric layer 144 and exposed portions of dielectric layer 144 may beetched to form trench 146. Subsequent to the etch process, the patternedphotoresist layer may be removed by a stripping process such as a wetetch, plasma etch, and/or a reactive ion etch stripping process. Such anetch process may, in some embodiments, be conducted in the same processchamber used to form trench 146. In some cases, the photoresist etchprocess may be conducted in the same process chamber used tosubsequently process semiconductor topography 140. For example, thephotoresist etch process may be conducted in the same process chamberused to electrolessly deposit material into trench 146. Although FIG. 11illustrates the formation of a single trench across the illustratedportion of dielectric layer 144, any number of trenches may be formedacross the dielectric layer in accordance with design specifications ofthe integrated circuit. In addition, although FIG. 11 illustrates trench146 extending from the upper surface of dielectric layer 144 to theupper surface of underlying layer 142, the method described herein isnot restricted to such a configuration of microelectronic topography140. In particular, the depth of trench 146 may be reduced, in someembodiments, such that underlying layer 142 is not exposed.

In general, the width and depth of trench 146 may be formed inaccordance with the design specifications of the integrated circuit. Forexample, the width of trench 146 may be between approximately 0.02microns and approximately 10 microns. In addition, the depth of trench146 may be between approximately 100 angstroms and approximately 1.0micron. However, larger or smaller widths and depths may be used,depending on the design specifications of the device. In someembodiments, the height (i.e., depth) and width of a semiconductorfeature when viewed in cross section may be described in relation toeach other and may be referred to as an “aspect ratio” of the feature.Consequently, the depth and width of trench 146 may, in someembodiments, be described in terms of an aspect ratio. In particular,the aspect ratio of trench 146 may between approximately 1:2 andapproximately 1:10. However, trench 146 may include larger or smalleraspect ratios, depending on the design specifications of the device.

As noted above, trench 146 may be used to subsequently form a metalfeature within microelectronic topography 140. As such, trench 146 maybe filled with a metal layer, such as aluminum, copper, tungsten,titanium, silver, or any alloy of such metals. “Metal layer”, as usedherein, may generally refer to any material comprising metal, includinglayers consisting essentially of a metal element and layers includingalloys or intermetallics of a metal element. The deposition of the metallayer forming the bulk of the metal feature within trench 146 isdescribed in more detail below in reference to FIG. 14. In some cases,however, liner layer 148 may be deposited within trench 146 prior to thedeposition of the bulk metal layer. Such a liner layer may serve toadhere the bulk metal layer to trench 146 and/or prevent diffusionbetween the bulk metal layer and underlying portions of microelectronictopography 140. For example, since copper diffuses readily throughsilicon and oxide and undesirably alters the electrical properties oftransistors formed in silicon, liner layer 148 may be deposited withintrench 146 before deposition of a bulk copper layer. Liner layer 148 maybe deposited within trench 146 before the deposition of other bulk metalmaterials as well. In yet other embodiments, the formation of linerlayer 148 may be omitted from microelectronic topography 140 and,therefore, the method described herein may continue onto to FIG. 14 fromFIG. 3.

As shown in FIG. 12, liner layer 148 may be formed conformably uponmicroelectronic topography 140 and, therefore, may be formed upon thelower surface and sidewalls of trench 146 as well as the upper surfacesof dielectric layer 144. Such a deposition process may include chemicalvapor deposition (CVD), physical vapor deposition (PVD), atomic layerdeposition (ALD), electroplating, or electroless plating techniques,depending on the material deposited. Consequently, the depositionsolution used to deposit liner layer 148 may depend on the material tobe deposited and the method of deposition. In any case, microelectronictopography 140 may be rinsed with deionized water subsequent to thedeposition of liner layer 148 to remove any residual depositionsolution. In general, the thickness of liner layer 148 may betweenapproximately 50 angstroms and approximately 1500 angstroms. Larger orsmaller thickness of liner layer 148, however, may be used, depending onthe design specifications of the device.

In some cases, liner layer 148 may include a metal material, such astantalum, tantalum nitride, tantalum silicon nitride, tantalum carbonnitride, silver, titanium, titanium nitride, titanium silicon nitride,titanium silicon nitride, tungsten, tungsten nitride, or refractoryalloys such as titanium-tungsten or copper-cadium. In some embodiments,liner layer 148 may include a combination of metal materials, such as astack of tantalum nitride and tantalum or a stack of titanium andtitanium nitride, for example. In some cases, it may be particularlyadvantageous for liner layer 148 to include a metal such that thecapacitance of the feature formed within trench 146 may be minimized. Inyet other embodiments, however, liner layer 148 may include a dielectricmaterial, such as silicon nitride, silicon carbide, silicon carbonnitride, silicon oxycarbide, silicon oxycarbon nitride, and/or anyorganic materials generally known for use in microelectronicfabrication. In any case, liner layer 148 may be hydrated as describedin more detail below in reference to FIG. 13. It is noted, however, thatliner layer 148 is not restricted to being hydrated and/or thecompositions listed above. In general, the materials listed for linerlayer 148 and the subsequent processing of liner layer 148 presentedherein are merely options available for forming a metal feature withinmicroelectronic topography 140. Such a statement may be applicable toutilizing a four-element liner layer discussed in more detail below aswell. In particular, the metal feature and method of forming the featuredescribed herein is not restricted to embodiments in which liner layer148 includes at least four elements.

As noted above, liner layer 148 may, in some embodiments, include asingle material comprising at least four elements. In particular, linerlayer 148 may include a single material comprising at least fourelements from the group consisting of boron, chromium, cobalt,molybdenum, nickel, phosphorus, rhenium, and tungsten. For example, insome cases, liner layer 148 may include a material comprising cobalt,tungsten, molybdenum and phosphorus. In other cases, liner layer 148 mayinclude a material comprising cobalt, tungsten, molybdenum and boron. Inany case, liner layer 148 may be formed as a single material layer suchthat no interfacial lines between layers of different compositions existwithin the layer. In other words, the elements within liner layer 148may be blended to characterize a layer of single material. Consequently,liner layer 148 may be distinguishable from a metal feature comprising aplurality of liner layers.

A “liner layer,” as used herein, may refer a layer conformably formedalong at least a portion of the sidewalls and/or lower surface of atrench such that a substantial portion of the trench prior to thedeposition of the layer remains unfilled after deposition of the layer.In some embodiments, the liner layer may be formed along the entirety ofthe sidewalls and lower surface of the trench as shown in FIG. 12. Inother embodiments, however, the liner layer may only be partially formedon the sidewalls and/or lower surface of the trench. In such anembodiment, the liner layer may either be selectively deposited orportions of the layer may be removed after a blanket deposition of thelayer within the trench. In either case, the liner layer may, in someembodiments, be arranged along portions of the topography adjacent tothe trench as shown in FIG. 12. Alternatively, the liner layer may notinclude the adjacent portions.

In general, liner layer 148 may include any combination of boron,chromium, cobalt, molybdenum, nickel, phosphorus, rhenium, and tungsten,depending on the design characteristics of the device. For example,liner layer 148 may include a combination of elements which isconfigured to adhere a bulk metal layer used to subsequently fill trench146. In addition or alternatively, liner layer 148 may include acombination of elements which is configured to substantially preventdiffusion between underlying layers of microelectronic topography 140and the bulk metal layer subsequently formed upon the liner layer. Insuch an embodiment, including molybdenum within liner layer 148 may beparticularly advantageous since molybdenum exhibits superior diffusionbarrier properties and has a high melting point. In any case, linerlayer 148 may, in some embodiments, include a combination of elementswhich is less susceptible to oxidation than a liner layer comprising amaterial with three or less elements. For example, liner layer 148 mayinclude products of oxidizing reducing agents, such as boron orphosphorus.

In some cases, liner layer 148 may include a combination of elementswhich is configured to serve as a catalyst for a subsequent electrolessdeposition of a bulk metal layer within trench 146. For example, linerlayer 148 may include a combination of elements which is configured toserve as a catalyst for a subsequent electroless deposition of copper orany other metal used to occupy a substantial portion of trench 146. Insuch an embodiment, liner layer 148 may preferably include cobaltand/nickel for their ability to form an autocatalytic surface.“Autocatalytic,” as used herein, may refer to the characteristic of amaterial to have electrochemical properties which exhibit an affinity tothe material to be deposited thereon. Consequently, an “autocatalytic”material may not have to be activated prior to an electroless depositionprocess since the material is already catalytic to the process. In someembodiments, however, an autocatalytic material may be activated priorto an electroless deposition process.

In some cases, liner layer 148 may include a majority of cobalt and/ornickel atoms. For example, liner layer 148 may include two or threeelements other than cobalt or nickel which each comprise betweenapproximately 0.1% and approximately 20% of a molar concentration of theliner layer. In particular, liner layer 148 may include one or twoelements having a molar concentration between approximately 0.1% andapproximately 20% which are selected from the group consisting ofchromium, molybdenum, rhenium, and tungsten. In addition, liner layer148 may include between approximately 0.1% and approximately 20% ofphosphorous and/or boron. The remaining balance of the molarconcentration of the layer may include cobalt and/or nickel.

Regardless of number of elements included within liner layer 148, themethod may further include hydrating microelectronic topography 140, insome cases. In particular, microelectronic topography 140 may be exposedto a hydrolysis process subsequent to the deposition of liner layer 148such that hydrated layer 150 may be formed as shown in FIG. 13. Forexample, in embodiments in which liner layer 148 includes tantalum,tantalic acid (H_(2x)Ta₂O_(5+x)) may be formed. In yet otherembodiments, liner layer 148 may include tantalum nitride, tantalumsilicon nitride, tantalum carbon nitride, titanium, titanium nitride,titanium silicon nitride, tungsten, tungsten nitride, or refractoryalloys such as titanium-tungsten with which to form a hydrated metaloxide layer. As noted above, the liner layer 148 may, in someembodiments, include a combination of such materials, such as a stack oftantalum nitride and tantalum or a stack of titanium and titaniumnitride, for example. In such an embodiment, a hydrated metal oxidelayer may be formed solely from the upper material of the stack or maybe formed from more than one material within the stack. In yet otherembodiments, liner layer 148 may not include a dielectric materialrather than a metal layer. For example, liner layer 148 may includesilicon nitride, silicon carbide, silicon carbon nitride, siliconoxycarbide, and/or silicon oxycarbon nitride. In such an embodiment,liner layer 148 may be hydrated to form a hydrated oxide materialwithout a metal component.

In any case, the hydrolysis process may include oxidizing liner layer148. As such, the hydrolysis process may include exposing liner layer148 to an oxidizing plasma, in some embodiments. In addition oralternatively, the hydrolysis process may include exposing liner layer148 to an oxidizing chemical, such as peroxide, in a liquid or gaseousstate. In yet other embodiments, the hydrolysis process may includeexposing the liner layer to ultraviolet photons in an oxidizing ambient.In such a case, the ultraviolet photons may be used to alter themolecular structure of the liner layer such that elements of the linerlayer may be oxidized. In any embodiment, the hydrolysis process mayfurther include exposing liner layer 148 to a chemical comprisinghydrogen, including any acid, base or neutral chemical includinghydrogen. For example, the hydrolysis process may further includeexposing liner layer 148 to sulfuric acid, hydrochloric acid, nitricacid, ammonia hydroxide, potassium hydroxide, or deionized water.

In general, the hydrolysis process used to form hydrated layer 150 mayeither partially or completely consume liner layer 148. In someembodiments, the hydration of liner layer 148 may consume an upperportion of the layer having a thickness between approximately 5angstroms and approximately 40 angstroms. As such, the thickness ofliner layer 148 may be reduced by such an amount during the hydrolysisprocess. In some cases, the hydrolysis process may cause a growth uponliner layer 148 in addition to consuming liner layer 148. In such anembodiment, the composite thickness of liner layer 148 and hydratedlayer 150 may be larger than the thickness of liner layer 148 prior tothe hydrolysis process. In particular, the composite thickness of linerlayer 148 and hydrated layer 150 may include a thickness betweenapproximately 50 angstroms and approximately 1600 angstroms. Morespecifically, hydrated layer 150 may include a thickness betweenapproximately 5 angstroms and approximately 50 angstroms. As notedabove, not all process steps described herein need to be included in theprocess of forming a metal feature within trench 146. As such, in someembodiments, the hydrolysis of liner layer 148 may be omitted. In eithercase, the process of forming a metal feature within trench 146 mayinclude cleaning liner layer 148 prior to the deposition of bulk metallayer 152. In particular, surface contaminants and/or oxides formed uponliner layer 148 may be removed prior to the formation of hydrated layer150 or directly prior to the deposition of bulk metal layer 152.

In general, hydrating liner layer 148 may be particularly advantageouswhen the bulk metal layer for the subsequently formed metal feature isdeposited using an electroless deposition process. In particular,hydrated layer 150 may serve to adsorb active catalytic metalssubsequently deposited upon microelectronic topography 140 such that abulk metal layer may be electrolessly deposited. More specifically,hydrated layer 150 may allow more active catalytic metals to be adsorbedas compared to a layer which has not been hydrated. Consequently, thesubsequent electroless deposition of bulk metal may be faster, moreuniform, and adhere more securely to trench 146. In some embodiments,hydrated layer 150 may be autocatalytic and, therefore, may not have tobe activated to initiate the electroless deposition process. In otherembodiments, however, hydrated layer 150 may have to be activated priorto electrolessly deposition bulk metal layer 152. Such an activationprocess may also be conducted when liner layer 148 is not hydrated. Ineither case, the activation process may include depositing a monolayerof cobalt, nickel, palladium, or platinum such that a seed layer of thematerial may be formed. In such an embodiment, the seed layer may bepatterned to be in alignment with trench 146 prior to the deposition ofbulk metal layer 152.

In yet other embodiments, however, the bulk metal layer subsequentlydeposited within trench 146 may not be electrolessly deposited. Rather,the bulk metal layer may be deposited using CVD, PVD, ALD, orelectroplating techniques, depending on the type of material beingdeposited. In such an embodiment, liner layer 148 and/or hydrated layer150 may not have to be activated. In some cases, liner layer 148 and/orbulk metal layer 152 may be deposited as oxidized materials and laterconverted into conductive metals by annealing the layers in a reducingambient. In any case, microelectronic topography 140 may be rinsed withdeionized water prior to the deposition of bulk metal layer 152. Morespecifically, microelectronic topography 140 may be rinsed subsequent tothe formation of hydrated layer 150 and/or subsequent to the depositionof the activation seed layer to remove any residual depositionsolutions. In general, bulk metal layer 152 may include a conductivematerial, such as aluminum, cadmium, copper, tungsten, titanium, silver,or any alloy of such metals. In this manner, the feature formed withintrench 146 may be used to electrically transmit signals within thedevice formed therefrom.

As shown in FIG. 14, bulk metal layer 152 may be deposited within trench146. In particular, bulk metal layer 152 may, in some embodiments, beformed conformably over microelectronic topography 140 such that thebulk metal layer is formed outside of trench 146 as well as inside thetrench. In yet other embodiments, however, bulk metal layer 152 may beselectively deposited within trench 146. Such a selective process mayinclude electrolessly depositing a bulk metal layer upon a liner layerwhich is catalytic to the electroless deposition process. For example,bulk metal layer 152 may be selectively deposited upon a liner layercomprising at least four elements as described above in reference toFIG. 12. In such an embodiment, portions of the liner layer formed uponthe upper surfaces of dielectric layer 144 may be removed prior to theelectroless deposition of the bulk metal layer. In this manner, the bulkmetal layer may not be deposited upon portions of microelectronictopography 140 arranged adjacent to trench 146. In such an embodiment,the bulk metal layer may be formed to a particular level within trench146. For example, bulk metal layer 152 may be formed to be substantiallycoplanar with the upper surfaces of dielectric layer 144 or justslightly below the upper surfaces of dielectric layer 144 such that roomwithin trench 146 remains for the deposition of a cap layer upon bulkmetal layer 152.

In yet other cases, bulk metal layer 152 may be deposited to a levelabove the upper surfaces of dielectric layer 144. In particular, bulkmetal layer 152 may be deposited to a thickness between 0.5 microns andapproximately 1.5 microns such that trench 146 is filled. Such aconfiguration may be particularly advantageous in an embodiment in whichbulk metal layer 152 is conformably formed across microelectronictopography 140 as shown in FIG. 14. In such an embodiment, portions ofbulk metal layer 152 deposited outside of trench 146 may be removed suchthat the metal feature within trench 146 may be substantially planarwith the upper surfaces of dielectric layer 144. Such a removal processmay include chemical mechanical polishing microelectronic topography 140or exposing the topography to an etch back process. In either case,portions of liner layer 148 and hydrated layer 150 deposited outside oftrench 146 may also be removed as shown in FIG. 14. Alternatively,portions of liner layer 148 and, in some embodiments, portions ofhydrated layer 150 arranged on the upper surfaces of dielectric layer144 may remain after the removal process such that bulk metal layer 152is substantially coplanar with either liner layer 148 or hydrated layer150. In any case, microelectronic topography 140 may be rinsed withdeionized water subsequent to the deposition of bulk metal layer 152 toremove any residual deposition solution.

In any case, microelectronic topography 140 may, in some embodiments, beannealed subsequent to the formation of bulk metal layer 152 withintrench 146. Such an anneal process may include subjectingmicroelectronic topography 140 to a temperature greater thanapproximately 400° C. In some cases, the anneal process may enhance theadhesion of bulk metal layer 152 within trench 146. In addition oralternatively, the anneal process may include dehydrating hydrated layer150 to form oxide layer 154 between bulk metal layer 152 and liner layer148, as shown in FIG. 15. For example, in an embodiment in whichhydrated layer 150 includes tantalic acid, a layer of tantalum pentoxidemay be formed between bulk metal layer 152 and liner layer 148. It isnoted that other oxide layers may alternatively be formed withinmicroelectronic topography 140, depending on the composition of hydratedlayer 150. In some embodiments, it may be particularly advantageous toform an oxide layer with metal such that the capacitance of the metalfeature formed within trench 146 may be minimized. Consequently, theprocess of hydrating liner layer 148 and dehydrating hydrated layer 150may be particularly advantageous when liner layer 148 includes a metal.In yet other embodiments, an oxide layer may not be formed within trench146. In particular, in embodiments in which hydrated layer 150 is notformed within the topography, an oxide layer may not be formed withinthe metal feature during the subsequent anneal process. In yet otherembodiments, the method for forming the metal feature as describedherein may not include an anneal process.

In some embodiments, it may be desirable to deposit a cap layer upon themetal feature formed within trench 146. Such a cap layer may serve toprevent diffusion between the metal feature and overlying layers. Inaddition or alternatively, the cap layer may serve to protect the metalfeature during subsequent processing. For example, the cap layer mayserve as a polishing stop layer or an etch stop layer such that themetal feature is not exposed or damaged. As such, the method describedherein may include the formation of a cap layer upon the metal featureformed within trench 146. In some cases, the formation of the cap layermay follow the sequence of steps described below in reference to FIGS.16-18. The method described herein, however, is not restricted to such asequence of process steps. In particular, the method may alternativelyinclude forming the cap layer upon the metal feature within trench 146without a deposition of a hydrophobic material upon adjacent portions ofdielectric layer 144 as described below in reference to FIG. 16. In thismanner, dielectric layer 144 may remain exposed prior to the depositionof the cap layer.

Referring to FIG. 16, in some embodiments, hydrophobic dielectric 156may be selectively deposited upon exposed surfaces of dielectric layer144. In this manner, dielectric layer 144 may be masked for thesubsequent deposition of cap layer 158. In some embodiments, it may bedesirable to mask dielectric layer 144 for the deposition of cap layer158. In particular, hydrophobic dielectric 156 may serve to prevent thedeposition of cap layer 158 upon dielectric layer 144. Morespecifically, a hydrophobic surface may advantageously prevent theabsorption of catalytic compounds, inhibiting the electroless depositionof materials upon hydrophobic dielectric 156, as described in moredetail below. In embodiments in which bulk metal layer 152 is polishedto be confined within the sidewalls of trench 146 (as described inreference to FIG. 15), dielectric layer 144 may include small fragmentsof bulk metal layer 152 upon its upper surface. The small fragments maybe catalytic to the electroless deposition of cap layer 158 or mayattract a catalytic seed layer used to electrolessly deposit cap layer158. In either case, portions of cap layer 158 may be undesirablydeposited upon dielectric layer 144, potentially causing a short withinthe circuit.

In some cases, dielectric layer 144 may be cleaned prior to thedeposition of cap layer 158 to remove the small fragments of bulk metallayer 152 formed within dielectric layer 144. In some embodiments,however, it may be difficult to determine if all fragments have beenremoved from such a process. As such, in some cases, the formation of ahydrophobic layer upon dielectric layer 144 may be more effective inpreventing the undesirable deposition of cap layer 158 on dielectriclayer 144. Although the deposition of hydrophobic dielectric 156 maynegate the need to remove the bulk metal fragments from dielectric layer144, the method described herein does not necessarily restrict theinclusion of such a cleaning step when a hydrophobic layer is to bedeposited upon dielectric layer 144. As such, cleaning dielectric layer144 may be performed whether or not a hydrophobic layer is formed withinmicroelectronic topography 140.

In general, hydrophobic dielectric 156 may include various forms ofhalogenated silanes and/or polymeric silanes. The polymeric silanematerials may be polymeric functional groups or may be a polymer withpolymeric silane functional groups. Use of either type of polymericsilane material may be particularly useful for sealing a porous surfaceof a low-k dielectric layer. More specifically, polymeric silanematerials may be advantageous for preventing moisture and components ofan electroless deposition solution into a low-k dielectric material,which may sometimes be used for dielectric layer 144. The selectivedeposition of hydrophobic dielectric 156 upon dielectric layer 144 mayinclude, for example, organic vapor phase deposition of any silanematerial configured to deposit a dielectric material in a halogenated orpolymeric form. For example, the selective deposition of hydrophobicdielectric 156 may include the organic vapor phase deposition ofdichlorodimethylsilane or dichloromethylsilane. Other silane materialthat may be additionally or alternatively used for the deposition ofhydrophobic dielectric 156 may include methyldichlorosilane,methyltrichlorosilane, trimethylchlorosilane, ethyldichlorosilane,ethyltrichlorosilane, methylethylchlorosilane, methyethyldichlorosilane,propyldichlorosilane, chloropropylmethyldichlorosilane,chloropropyltrichlorosilane, vinyltrichlorosilane,vinylmethyldichlorosilane, phenyltrichlorosilane,diphenyldichlorosilane, phenylmethyldichlorosilane,phenylethyldichlorosilane, trichlorosilane, polyalkenedichlorosilane,polymethylenedichlorosiolane (TBD), and polyethylenedichlorosilane.

In any case, the selective deposition of hydrophobic dielectric layer156 may also include exposing the substrate to deionized water. Inparticular, exposing microelectronic topography 140 to deionized waterduring or after the deposition of hydrophobic dielectric 156 may serveto hydrolyze the silane material absorbed within dielectric layer 144and remove any hydrochloric acid such that a strong bond betweenhydrophobic 156 and dielectric layer 144 may be formed. In general, thethickness of hydrophobic dielectric 156 may be between approximately 5angstroms and approximately 500 angstroms. However, larger or smallerthicknesses of hydrophobic dielectric 156 may be deposited, depending onthe design specifications of the device. For example, in someembodiments, it may be advantageous to deposit hydrophobic dielectric156 to a thickness less than approximately 500 angstroms such that thestep height of cap layer 158 above dielectric layer 144 is minimized.

As noted above, the deposition of hydrophobic dielectric 156 may beadvantageous for preventing the deposition of cap layer 158 uponportions of microelectronic topography 140 other than above trench 146,particularly in embodiments in which cap layer 158 is electrolesslydeposited. More specifically, since layer 156 is a dielectric material,it will not be catalytic to the deposition of cap layer 158. Inaddition, layer 156 may prohibit solution adsorption onto the layersince it is hydrophobic. In general, hydrophilic materials, such asthose used for dielectric layer 144, may be susceptible to adsorbingcatalytic ions from an activation solution, particularly solutionsincluding palladium ions. As a result, a material subsequently depositedupon microelectronic topography 140 using electroless depositiontechniques may be formed upon dielectric layer 144 as well as abovetrench 146. Since layer 156 is hydrophobic, however, the deposition ofcap layer upon portions of microelectronic topography 140 other thanabove the metal feature within trench 146 may be avoided.

In general, cap layer 158 may be deposited upon microelectronictopography 140 as shown in FIG. 17. As noted above, in some embodiments,cap layer 158 may be electrolessly deposited upon microelectronictopography 140 and, therefore, may be selectively deposited upon themetal feature within trench 146. In some embodiments, bulk metal layer152 may be catalytic to the deposition of cap layer 158 and, therefore,the deposition of a catalytic seed layer upon the bulk metal layer maynot be needed. However, in some embodiments, bulk metal layer 152 may bea slow catalyst to the electroless deposition of cap layer 158,undesirably limiting the deposition rate of cap layer 158. For example,a bulk metal layer of copper may be a slow catalyst to the electrolessdeposition of a cap layer of cobalt, tungsten, and phosphorus. In yetother embodiments, bulk metal layer 152 may not be catalytic to thedeposition of cap layer 158 at all.

As such, in some embodiments, a catalytic seed layer may be depositedupon microelectronic topography 140 prior to the deposition of cap layer158 to enable and/or enhance the selective electroless deposition of thecap layer upon the metal feature within trench 146. In particular, amonolayer of cobalt, nickel, palladium, or platinum may be depositedupon microelectronic topography 140 and subsequently patterned to be inalignment with the metal feature within trench 146 prior to thedeposition of cap layer 158. In such an embodiment, microelectronictopography 140 may, in some cases, be rinsed in order to remove anydeposition residue of the seed layer prior to the deposition of caplayer 158. In yet other embodiments, cap layer 158 may be conformablydeposited across microelectronic topography 140 and patterned to alignwith the metal feature in trench 146. As such, cap layer 158 may bedeposited by processes other than electroless deposition techniques. Inparticular, cap layer 158 may be deposited by CVD, PVD, ALD, orelectroplating techniques. In general, cap layer 158 may be formed to athickness between approximately 5 angstroms and approximately 50angstroms. Larger or smaller thicknesses of cap layer 158 may bedeposited, however, depending on the design specifications of thedevice. In any case, microelectronic topography 140 may be cleanedand/or rinsed subsequent to the deposition of cap layer 158 to removeany deposition residue that may have been sparsely formed uponhydrophobic dielectric 156.

In general, cap layer 158 may include one or more elements which areconfigured to substantially prevent diffusion between bulk metal layer152 and subsequently formed overlying layers of microelectronictopography 140. For example, cap layer 158 may include a metal material,such as tantalum, tantalum nitride, tantalum silicon nitride, tantalumcarbon nitride, titanium, titanium nitride, titanium silicon nitride,tungsten, tungsten nitride, or refractory alloys such astitanium-tungsten. In some embodiments, the liner layer 148 may includea combination of such materials, such as a stack of tantalum nitride andtantalum or a stack of titanium and titanium nitride, for example. Inyet other embodiments, cap layer 158 may include any combination ofboron, chromium, cobalt, molybdenum, nickel, phosphorus, rhenium, andtungsten, depending on the design characteristics of the device. Inparticular, cap layer 158 may include a single material comprising atleast four of such elements as described above in reference to FIG. 12.In yet other embodiments cap layer 158 may include two or three of suchelements. For instance, cap layer 158 may include cobalt, tungsten andphosphorus. Other combinations of the aforementioned elements may bepossible, depending on the design characteristics of the device.

As shown in FIG. 17, a microelectronic topography may be formed whichincludes a metal feature having cap layer 158 formed upon and in contactwith bulk metal layer 152. In addition, the microelectronic topographymay include a dielectric portion including a lower surface substantiallycoplanar with a lower surface of the metal feature and having a lowerlayer of hydrophilic material and an upper layer of hydrophobicmaterial. As noted above, dielectric layer 144 may include a dielectricmaterial such as silicon dioxide, silicon nitride, or siliconoxynitride. All such materials are hydrophilic materials, so thedielectric portion of the aforementioned microelectronic topography mayrefer to hydrophobic dielectric 156 formed upon and in contact withdielectric layer 144.

As shown in FIG. 18, hydrophobic dielectric 156 may be removedsubsequent to the deposition of cap layer 158, in some embodiments. Sucha removal process may include wet or dry etching techniques, such asprocesses using solvent-based fluids and/or dissolved ozone water,supercritical cleaning techniques, ultraviolet ablation, and/or plasmaetching. In some embodiments, only the hydrophobic surface layer ofhydrophobic dielectric 156 may be removed by such a process. In yetother embodiments, however, hydrophobic dielectric 156 may not beremoved at all. In particular, hydrophobic dielectric 156 may remainwithin microelectronic topography 140 for subsequent processing. Forexample, hydrophobic layer 156 may be used to adhere a subsequentlydeposited layer. In addition or alternatively, hydrophobic layer 156 maybe used as an etch stop layer. In such an embodiment, some of thehydrogen atoms within hydrophobic layer 156 may be replaced with aminogroups to produce a material with a higher etch selectivity.

In some cases, microelectronic topography 140 may be further processedto form additional layers and structures above the contact structureformed within trench 146. For example, in some embodiments,microelectronic topography 140 may be exposed to processes which formdielectric and/or conductive features upon the contact structure. Insome embodiments, an additional layer may be formed upon cap layer 158to improve the adhesion of the cap layer to subsequently formedoverlying layers and structures. In some cases, the additional layer mayadditionally or alternatively serve as a diffusion barrier for thecontact structure. In yet other embodiments, the additional layer mayserve as an etch stop layer. In such an embodiment, the additional layermay be blanketed deposited across microelectronic topography 140 suchthat the additional layer resides upon portions adjacent to cap layer158 as well as cap layer 158. In any case, the additional layer mayinclude siloxanes, amino-compounds, hetero-atomic organic compounds, orinorganic compounds, for example.

It will be appreciated to those skilled in the art having the benefit ofthis disclosure that this invention is believed to provide a system andmethods for processing a microelectronic topography. Furthermodifications and alternative embodiments of various aspects of theinvention will be apparent to those skilled in the art in view of thisdescription. For example, although the process chamber and methodsprovided herein are frequently described in reference to process stepsconducted prior to, during, and subsequent to an electroless depositionprocess, the system and methods are not necessarily restricted to suchprocesses. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as the presently preferred embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims.

1. A method of minimizing the accumulation of bubbles upon a waferduring an electroless deposition process, comprising: loading the waferinto an electroless deposition chamber; sealing the electrolessdeposition chamber to form an enclosed area about the wafer; supplying adeposition solution to the enclosed area via a moveable dispense devicearranged above the wafer; and agitating the deposition solution tocreate an amount of motion sufficient to form a layer havingsubstantially uniform thickness, wherein the step of agitating comprisesmoving a brush comprising the moveable dispense device through thedeposition solution at a level spaced above the wafer.
 2. The method ofclaim 1, wherein the step of agitating is sufficient to create laminaragitation within the deposition solution.
 3. The method of claim 1,further comprising pressurizing the enclosed area to a pressure betweenapproximately 5 psi and approximately 100 psi during the electrolessdeposition process.
 4. The method of claim 1, further comprisingpressurizing the enclosed area to a pressure of approximately 50 psiduring the electroless deposition process.